MKV Cutter x264 level argument error

[Selur]

Problem is that you are not trying to cut H.264, but H.265 content frame accurate.
(MKV Cutter, can be 'misused' to cut H.265 content but only key-frame not frame accurate.)
x264 can only create H.264 content and H.265 has Profile@Level@Tier while H.264 only has Profile@Level, which is why the extraction of the level fails.

Cu Selur