Bug 507614

SUMMARY
Link to the project file, [https://github.com/nuxttux/Kdenlive_Crashes/tree/main/Render_Crashes] Multiply_Demo_V1.

The render / export would consistently crash at different points in the process.
I tried different render profile and it still crashed. 
The one that worked was exporting as an image sequence, jpg.

STEPS TO REPRODUCE
1. Open project.
2. Enable Parallel processing.
3. Render / Export Project as MP4 or MOV

OBSERVED RESULT
.Export starts and crashed at some point with error message:
/usr/include/c++/14.2.0/bits/stl_vector.h:1130: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = frei0r::param_info; _Alloc = std::allocator<frei0r::param_info>; reference = frei0r::param_info&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.Rendering

.Or with error message:
corrupted double-linked listRendering

EXPECTED RESULT
For the render / export to complete.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0

ADDITIONAL INFORMATION
The render completes without crashing if Parallel processing is turned off, but it takes up to 20 - 40 minutes to complete.