I ran into this issue today on a server of ours. We have a cPanel account with a disk quota of 5.5GB. That was adjusted up from 4GB in Apr 2017. I log in today and WHM reports that the account is at 5520/5500 and thus it's at max capacity. I go into the cPanel to investigate what the user did and I find that cPanel is reporting they have 11GB worth of email. Now... in Apr 2017 they were below the 4GB limit. We increased it to give them time to clean up their email which apparently they never did. But how did they exceed the limit by almost double? Shouldn't WHM be stopping mail delivery once its full? Additionally, in the breakdown screenshot, all the accounts summed is about 7.1GB. I can't find where the other 3.8GB is coming from that cPanel is reporting to make the full 11GB.
I had to manually suspend the account today since the website was still up and functional and they were still receiving email without an issue at all. Any input on what happened is appreciated.

I had to manually suspend the account today since the website was still up and functional and they were still receiving email without an issue at all. Any input on what happened is appreciated.

