Why is Gurobi taking so much time to find the optimal solution to objective 2?

Hi, I have a question regarding algorithms. I've built a model with a relatively complex expression of objective 1 and a relatively simple expression of objective 2. The codes are as follows (in Python) :

lgtp=slot_allocation.addVars(D,lb=3,ub=3.3,vtype=GRB.CONTINUOUS,name='lgtp')
for d in D:
    slot_allocation.addGenConstrLogA(tp[d],lgtp[d],10.0, "FuncPieces=-1 FuncPieceError=1e-6")
tp3=slot_allocation.addVars(D,O_north,lb=30,ub=4000,vtype=GRB.CONTINUOUS, name = "temp3")
for d in D:
    for ono in O_north:
        slot_allocation.addConstr(gp.quicksum(flightprocedure[m,d]*math.pow(10,0.1*EPNL_alt[m,d,ono])+\
            (1-flightprocedure[m,d])*math.pow(10,0.1*EPNL_ori[m,d,ono]) for m in M)/N[d]/100000==tp3[d,ono])
lgtp3=slot_allocation.addVars(D,O,lb=1.4,ub=3.8,vtype=GRB.CONTINUOUS,name='lgtp2')
for d in D:
    for ono in O_north:
        slot_allocation.addGenConstrLogA(tp3[d,ono],lgtp3[d,ono],10.0, "FuncPieces=-1 FuncPieceError=1e-6") 
noise=gp.quicksum(10*(lgtp3[d,ono]+5)+10*lgtp[d]-39.4 for d in D for ono in O_north)

total_displacement = gp.quicksum(abs(t-Tdm[d][m])*flightslot[m,d,t] for d in D for m in M for t in T)
slot_allocation.setObjectiveN(noise,0,2,GRB.MINIMIZE)
slot_allocation.setObjectiveN(total_displacement,1,1,GRB.MINIMIZE)

When Gurobi solves the model, it quickly gets the optimal solution to objective 1. However, it takes such a long time to find the optimal solution to objective 2 with large gap (I set TimeLimit=3600). Why does this happen? 

Gurobi Optimizer version 10.0.0 build v10.0.0rc2 (win64)

CPU model: 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz, instruction set [SSE2|AVX|AVX2|AVX512]
Thread count: 4 physical cores, 8 logical processors, using up to 8 threads

Optimize a model with 95596 rows, 1555757 columns and 14658989 nonzeros
Model fingerprint: 0x5d12a1eb
Model has 14 quadratic constraints
Model has 21 general constraints
Variable types: 63 continuous, 1555694 integer (1555687 binary)
Coefficient statistics:
  Matrix range     [7e-05, 3e+02]
  QMatrix range    [1e+00, 1e+00]
  Objective range  [1e+00, 3e+02]
  Bounds range     [1e+00, 4e+03]
  RHS range        [1e+00, 3e+03]
  QRHS range       [9e+05, 9e+05]

---------------------------------------------------------------------------
Multi-objectives: starting optimization with 2 objectives ... 
---------------------------------------------------------------------------

Multi-objectives: applying initial presolve ...
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Presolve removed 85814 rows and 1481549 columns
Presolve time: 3.35s
Presolved: 9796 rows and 74208 columns
---------------------------------------------------------------------------

Multi-objectives: optimize objective 1 () ...
---------------------------------------------------------------------------

Presolve removed 8470 rows and 64803 columns (presolve time = 6s) ...
Presolve removed 8470 rows and 64815 columns
Presolve time: 5.89s
Presolved: 1328 rows, 9393 columns, 83509 nonzeros
Presolved model has 1 bilinear constraint(s)
Variable types: 452 continuous, 8941 integer (8881 binary)

Root simplex log...

Iteration    Objective       Primal Inf.    Dual Inf.      Time
       0    1.0153578e+03   8.959817e+02   0.000000e+00     10s
    1099    1.0360908e+03   0.000000e+00   0.000000e+00     10s

Root relaxation: objective 1.036091e+03, 1099 iterations, 0.02 seconds (0.02 work units)

    Nodes    |    Current Node    |     Objective Bounds      |     Work
 Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time

     0     0 1036.09079    0   25          - 1036.09079      -     -    9s
H    0     0                    1041.8602860 1036.09079  0.55%     -    9s
     0     0 1040.94705    0   34 1041.86029 1040.94705  0.09%     -    9s
     0     0 1041.78509    0   28 1041.86029 1041.78509  0.01%     -    9s

Cutting planes:
  Gomory: 10
  RLT: 1

Explored 1 nodes (1683 simplex iterations) in 9.85 seconds (11.88 work units)
Thread count was 8 (of 8 available processors)

Solution count 1: 1041.86 

Optimal solution found (tolerance 1.00e-04)
Best objective 1.041860286020e+03, best bound 1.041785091838e+03, gap 0.0072%
---------------------------------------------------------------------------

Multi-objectives: optimize objective 2 () ...
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Loaded user MIP start with objective 18221

Presolve removed 226 rows and 6054 columns
Presolve time: 0.90s
Presolved: 9585 rows, 68154 columns, 602515 nonzeros
Presolved model has 7 bilinear constraint(s)
Found heuristic solution: objective 18197.000000
Variable types: 3151 continuous, 65003 integer (64581 binary)
Found heuristic solution: objective 10501.000000
Deterministic concurrent LP optimizer: primal simplex, dual simplex, and barrier
Showing barrier log only...

Root barrier log...

Ordering time: 0.00s

Barrier statistics:
 AA' NZ     : 1.089e+05
 Factor NZ  : 2.413e+05 (roughly 20 MB of memory)
 Factor Ops : 8.968e+06 (less than 1 second per iteration)
 Threads    : 2

                  Objective                Residual
Iter       Primal          Dual         Primal    Dual     Compl     Time
   0   6.55644408e+07 -5.73662353e+05  6.34e+04 1.32e+01  2.92e+03    11s

Barrier performed 0 iterations in 11.31 seconds (13.81 work units)
Barrier solve interrupted - model solved by another algorithm

Solved with dual simplex

Use crossover to convert LP symmetric solution to basic solution...

Root crossover log...

 0 DPushes remaining with DInf 0.0000000e+00                11s

     432 PPushes remaining with PInf 0.0000000e+00                11s
       0 PPushes remaining with PInf 0.0000000e+00                11s

  Push phase complete: Pinf 0.0000000e+00, Dinf 0.0000000e+00     11s

Root simplex log...

Iteration    Objective       Primal Inf.    Dual Inf.      Time
    1845    2.0700000e+02   0.000000e+00   0.000000e+00     11s
    1845    2.0700000e+02   0.000000e+00   0.000000e+00     11s

Root relaxation: objective 2.070000e+02, 1845 iterations, 0.56 seconds (0.44 work units)

    Nodes    |    Current Node    |     Objective Bounds      |     Work
 Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time

     0     0  207.00000    0  118 10501.0000  207.00000  98.0%     -   11s
H    0     0                    8098.0000000  207.00000  97.4%     -   12s
     0     0  207.00000    0  137 8098.00000  207.00000  97.4%     -   12s
     0     0  207.00000    0  137 8098.00000  207.00000  97.4%     -   13s

......

Cutting planes:
  Gomory: 152
  Lift-and-project: 2
  MIR: 140
  StrongCG: 9
  Flow cover: 3
  RLT: 3

Explored 96584 nodes (7151677 simplex iterations) in 3600.12 seconds (2662.39 work units)
Thread count was 8 (of 8 available processors)

Solution count 10: 5195 5203 5207 ... 5222

Time limit reached
Best objective 5.195000000000e+03, best bound 5.126000000000e+03, gap 1.3282%

---------------------------------------------------------------------------
Multi-objectives: stopped in 3602.40 seconds (2662.39 work units), solution count 10
Time Limit reached