DivX is creating bad remuxes

Everytime I convert a video to h.265 using DivX software I have to remux the files again using MKVtoolnix because the file created after a conversion is done won't play correctly or won't play at all on some of my devices.

When I remux the file using MKVToolnix I always get this error message:

--- Warnings emitted by job 'Multiplexing to file "filename.mkv" in directory "D:\Folder"' started on 2020-10-17 09:21:33 -05:00 ---
D:\Folder\filename.mkv: Error in the Matroska file structure at position 542076622. Resyncing to the next level 1 element.
The last timestamp processed before the error was encountered was 00:43:39.909000000.
Resync failed: no valid Matroska level 1 element found.

Every single file I convert using DivX get a similar error as above so the only way to fix the problem is to remux it again.

After that, most videos play correctly but others get the audio not synced with the video even after a new remux.

I am a DivX Pro user using the latest version of the software running on the lastest version of Windows 10.