wrong solution due to numeric issues

Hi gurobi support team

I find a wrong solution due to numeric issues with the warning:'Warning: 1 variables dropped from basis'.Here is the log:

Set parameter Username
Set parameter TimeLimit to value 240
Set parameter MIPGap to value 0
Set parameter CrossoverBasis to value 0
Set parameter MIPFocus to value 2
Set parameter NodefileDir to value ""
Set parameter DualReductions to value 0
Set parameter PreSOS2BigM to value 0
Set parameter TuneTrials to value 3
Academic license - for non-commercial use only - expires 2024-06-06
Gurobi Optimizer version 10.0.1 build v10.0.1rc0 (win64)

CPU model: 11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz, instruction set [SSE2|AVX|AVX2|AVX512]
Thread count: 8 physical cores, 16 logical processors, using up to 16 threads

Optimize a model with 62216 rows, 18265 columns and 1373301 nonzeros
Model fingerprint: 0x7a828e2e
Model has 10560 quadratic objective terms
Variable types: 16609 continuous, 1656 integer (1656 binary)
Coefficient statistics:
  Matrix range     [1e-03, 5e+02]
  Objective range  [1e+00, 1e+05]
  QObjective range [7e+01, 1e+02]
  Bounds range     [1e+00, 1e+00]
  RHS range        [8e-03, 3e+06]
Presolve added 0 rows and 623 columns
Presolve removed 32100 rows and 0 columns
Presolve time: 1.90s
Presolved: 30116 rows, 18888 columns, 258086 nonzeros
Presolved model has 8410 quadratic objective terms
Variable types: 17540 continuous, 1348 integer (1345 binary)
Found heuristic solution: objective 2.099126e+07
Root relaxation presolved: 27046 rows, 21905 columns, 200196 nonzeros
Root relaxation presolved model has 8410 quadratic objective terms


Root simplex log...

Iteration    Objective       Primal Inf.    Dual Inf.      Time
   19632    9.5153347e+07   0.000000e+00   2.947583e+06      5s
Warning: 1 variables dropped from basis
   77630    3.1817092e+06   0.000000e+00   4.071732e+06     10s
Warning: 1 variables dropped from basis
Warning: 1 variables dropped from basis
Warning: 1 variables dropped from basis

Root relaxation: infeasible, 97928 iterations, 9.68 seconds (22.36 work units)

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

     0     0 infeasible    0      2.0991e+07 2.0991e+07  0.00%     -   12s

Explored 1 nodes (97928 simplex iterations) in 12.79 seconds (30.59 work units)
Thread count was 16 (of 16 available processors)

Solution count 1: 2.09913e+07 

Optimal solution found (tolerance 0.00e+00)
Best objective 2.099126229359e+07, best bound 2.099126229359e+07, gap 0.0000%

However,after I turn off the presolve,the solution goes well:

Set parameter Username
Set parameter TimeLimit to value 240
Set parameter MIPGap to value 0
Set parameter CrossoverBasis to value 0
Set parameter MIPFocus to value 2
Set parameter NodefileDir to value ""
Set parameter DualReductions to value 0
Set parameter Presolve to value 0
Set parameter PreSOS2BigM to value 0
Set parameter TuneTrials to value 3
Academic license - for non-commercial use only - expires 2024-06-06
Gurobi Optimizer version 10.0.1 build v10.0.1rc0 (win64)

CPU model: 11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz, instruction set [SSE2|AVX|AVX2|AVX512]
Thread count: 8 physical cores, 16 logical processors, using up to 16 threads

Optimize a model with 62216 rows, 18265 columns and 1373301 nonzeros
Model fingerprint: 0x7a828e2e
Model has 10560 quadratic objective terms
Variable types: 16609 continuous, 1656 integer (1656 binary)
Coefficient statistics:
  Matrix range     [1e-03, 5e+02]
  Objective range  [1e+00, 1e+05]
  QObjective range [7e+01, 1e+02]
  Bounds range     [1e+00, 1e+00]
  RHS range        [8e-03, 3e+06]
Variable types: 16609 continuous, 1656 integer (1656 binary)
Found heuristic solution: objective 8574453.6353

Root simplex log...

Iteration    Objective       Primal Inf.    Dual Inf.      Time
   21735    1.2338445e+06   1.976190e+05   0.000000e+00      5s
   39771    1.5543817e+06   0.000000e+00   0.000000e+00      9s

Root relaxation: objective 1.554382e+06, 39771 iterations, 4.74 seconds (20.56 work units)

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

H    0     0                    1914319.2312 1554381.71  18.8%     -    9s
     0     0 1555222.58    0  247 1914319.23 1555222.58  18.8%     -    9s
     0     0 1555222.58    0  221 1914319.23 1555222.58  18.8%     -    9s
     0     0 1555222.58    0  225 1914319.23 1555222.58  18.8%     -    9s
     0     0 1561186.90    0   52 1914319.23 1561186.90  18.4%     -   11s
     0     0 1561199.39    0   49 1914319.23 1561199.39  18.4%     -   11s
H    0     0                    1600434.1349 1561199.39  2.45%     -   12s
     0     0 1562703.43    0   25 1600434.13 1562703.43  2.36%     -   13s
     0     0 1562704.45    0   23 1600434.13 1562704.45  2.36%     -   13s
H    0     0                    1599980.8026 1562704.45  2.33%     -   14s
     0     0 1562711.60    0   26 1599980.80 1562711.60  2.33%     -   14s
H    0     0                    1567865.5149 1562711.60  0.33%     -   15s
     0     0 1562713.41    0   30 1567865.51 1562713.41  0.33%     -   16s
     0     0 1562713.41    0   30 1567865.51 1562713.41  0.33%     -   17s
     0     0 1562713.42    0   31 1567865.51 1562713.42  0.33%     -   17s
     0     0 1562713.42    0   31 1567865.51 1562713.42  0.33%     -   19s
     0     2 1562713.42    0   31 1567865.51 1562713.42  0.33%     -   20s
H   32    40                    1564546.5097 1563457.40  0.07%  86.5   23s
H   34    40                    1564335.6704 1563457.40  0.06%  82.3   23s
H   38    40                    1564233.8539 1563463.46  0.05%  78.5   23s
   108    58     cutoff    8      1564233.85 1563505.17  0.05%  72.3   25s
   292    49 1563994.89   10   14 1564233.85 1563611.01  0.04%  60.9   30s
*  367    42              14    1564209.2674 1563690.14  0.03%  59.6   32s
   483     9     cutoff    8      1564209.27 1563931.01  0.02%  56.9   35s

Cutting planes:
  Gomory: 10
  Implied bound: 436
  MIR: 2
  Flow cover: 74
  RLT: 50
  Relax-and-lift: 69

Explored 532 nodes (71456 simplex iterations) in 36.42 seconds (108.15 work units)
Thread count was 16 (of 16 available processors)

Solution count 9: 1.56421e+06 1.56423e+06 1.56434e+06 ... 8.57445e+06

Optimal solution found (tolerance 0.00e+00)
Best objective 1.564209267417e+06, best bound 1.564209267417e+06, gap 0.0000%

I have 2 questions:

1.what does the message 'Warning: 1 variables dropped from basis' mean?

2.Can I avoid this mistake without the sacrifice of efficiency(say,turning off presolve).

Thanks in advance.