My recording software sometimes (rarely) duplicates or misplaces frames in a recording. In a not very competitive category it this ok? Can the time still be verifyed?

You need to ask the mods of the game in question what they consider to be "good enough" proof.

As an aside, idk what software you're using to record runs but I would recommend switching to OBS which is the defacto standard of recording right now.

thanks for the advice!