Firstly, I would strongly discourage against using game_restart(), especially in GMS1 - it will leak every single dynamic thing that you have made (be it data structures, dynamically loaded assets, etc.), will not reset global variables (meaning that if you’re trying to access a not-yet-set global, you’ll get the value from before game_restart()), and otherwise introduce undefined behaviour. For extensions, it runs their “init” code (which is supposed to only run on game start) the second time, which requires workarounds just for that purpose.
Then, you are saying “5 files” - are you manually extracting the GMEZ instead of adding the extension via Extensions - Import Extension? I cannot reproduce this on my end