I recently upgraded from mIRC v6.21 to v6.3, and I noticed a strange bug - Despite having "Except status" checked in logging options, my client has been logging the status window. I noticed it after being re-connected from a net blip. I even tried making it read only, and mIRC unlocks it. The temporary solution is to revoke the write privilege in the file's security tab for whatever user mIRC is running on.

I also noticed, after the upgrade, some logs had been going to the Main folder rather than the network folders. I am not sure exactly how to reproduce this, but I noticed it.