The Rockstar Editor in FiveM writes a custom format that the base game does not understand so that resources can be loaded to make the recording work correctly.
If you’re having issues loading your clips in FiveM, try loading into FiveM loadlevel gta5 and then loading your clip as a workaround if your server does not support unloading/reconnecting, alternately report a repro of the map/other resources you use that fail to unload.