I have a table with model set to QSqlQueryModel, which acquires data from MySQL server.
I connected the doubleClicked signal to a slot so I can open a dialog with data of the selected row, on which I have a reject and accept button.
If I reject, there is no problem, the dialog closes, If I accept on the other hand, the whole app crashes.
Here is another thing that you need to know, for that table I added another shortcut which activates when pressing Return key and this issue does not occur when I open the dialog using the Return key, just when opening with doubleclick.

Here is what I get when using debugger:
Qt Code: 
  1. Function: _ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent
  2. 0x7ffff791bff6  <+0x01f6>         or     $0xe8ef8948,%eax
  3. 0x7ffff791bffb  <+0x01fb>         jno    0x7ffff791bf80 <_ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent+384>
  4. 0x7ffff791bffd  <+0x01fd>         (bad)
  5. 0x7ffff791bfff  <+0x01ff>         jmpq   0x7ffff791bf52 <_ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent+338>
  6. 0x7ffff791c004  <+0x0204>         mov    (%rbx),%rax
  7. 0x7ffff791c007  <+0x0207>         mov    %rbp,%rdi
  8. 0x7ffff791c00a  <+0x020a>         mov    0x2d0(%rax),%r13
  9. 0x7ffff791c011  <+0x0211>         callq  0x7ffff76c43c0 <_ZNK21QPersistentModelIndexcvRK11QModelIndexEv@plt>
  10. 0x7ffff791c016  <+0x0216>         mov    %r12,%rcx
  11. 0x7ffff791c019  <+0x0219>         mov    $0x2,%edx
  12. 0x7ffff791c01e  <+0x021e>         mov    %rax,%rsi
  13. 0x7ffff791c021  <+0x0221>         mov    %rbx,%rdi
  14. 0x7ffff791c024  <+0x0224>         callq  *%r13
  15. 0x7ffff791c027  <+0x0227>         test   %al,%al
  16. 0x7ffff791c029  <+0x0229>         jne    0x7ffff791bff7 <_ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent+503>
  17. 0x7ffff791c02b  <+0x022b>         mov    %rbx,%rdi
  18. 0x7ffff791c02e  <+0x022e>         callq  0x7ffff76fe5f0 <_ZNK7QWidget5styleEv>
  19. 0x7ffff791c033  <+0x0233>         mov    (%rax),%r9
  20. 0x7ffff791c036  <+0x0236>         xor    %r8d,%r8d
  21. 0x7ffff791c039  <+0x0239>         xor    %edx,%edx
  22. 0x7ffff791c03b  <+0x023b>         mov    %rbx,%rcx
  23. 0x7ffff791c03e  <+0x023e>         mov    $0x3d,%esi
  24. 0x7ffff791c043  <+0x0243>         mov    %rax,%rdi
  25. 0x7ffff791c046  <+0x0246>         callq  *0xf0(%r9)
  26. 0x7ffff791c04d  <+0x024d>         test   %eax,%eax
  27. 0x7ffff791c04f  <+0x024f>         jne    0x7ffff791bff7 <_ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent+503>
  28. 0x7ffff791c051  <+0x0251>         mov    %rbp,%rdi
  29. 0x7ffff791c054  <+0x0254>         callq  0x7ffff76c43c0 <_ZNK21QPersistentModelIndexcvRK11QModelIndexEv@plt>
  30. 0x7ffff791c059  <+0x0259>         mov    %rbx,%rdi
  31. 0x7ffff791c05c  <+0x025c>         mov    %rax,%rsi
  32. 0x7ffff791c05f  <+0x025f>         callq  0x7ffff791ae30 <_ZN17QAbstractItemView9activatedERK11QModelIndex>
  33. 0x7ffff791c064  <+0x0264>         jmp    0x7ffff791bff7 <_ZN17QAbstractItemView21mouseDoubleClickEventEP11QMouseEvent+503>
  34. 0x7ffff791c066  <+0x0000>         nopw   %cs:0x0(%rax,%rax,1)
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