pdagenius This could also be a warning of an exploit. You maybe shouldn't be super quick to just disable hardened_malloc, since memory corruption is the largest class of security bugs and this is what hardened_malloc defends against. Most likely the app isn't playing well with the hardened memory allocator, but if this or a memory tagging error ever happen to me I like to see if it happens again if I uninstall the app and reinstall it from a trusted source (Play Store) and see that it happens over and over predictability.
I also send the error logs to the app developer, since its them that needs to fix their app, not GrapheneOS that needs to fix anything.