Mega Backups fails (+ MFA Setup)

This issue had the same error and stack trace, but it was said to be resolved with an update:

There is also this forum post:

Neither of those seem to indicate a connection to the file sizes, but maybe nobody ever noticed. If you can reliably reproduce the error, you might be up to something.

It might help others to reproduce if you post your job configuration (without passwords and other sensitive data).