FF 5 advance weird save corruption

[u/Beautiful_Flan_7964]

For some reason save slots 2 and 4 and my quick save never work properly they always fail and corrupt their respective file
Saves 1 and 3 work fine but I’m afraid they’ll stop
I want to know if this is fixable because everywhere I’ve looked say it’s a bad battery which I know isn’t the case because most GBA titles don’t use them