once I noticed failures on my ventoy pendrive because a specific bootable system had unexpected bugs each time I booted it. after I have rewritten it from backup, it was working fine again.

but bitrot works this way not just on pendrives, but SSDs and HDDs too. the system won't know unless it tries to read the file. SMART selftests may help. but even then, what good it is if it does not let you know actively?