I installed the latest 5.2 load to both our development and hosting site and observed the same result.
I have rolled back to the previous 5.2 load (the version with ICSharp lib) as it is a showstopper as our writers can't access any existing files on-site. Everthing goes back to normal except the "mailto" issue.
All we want is a fix to "mailto" but in the process, we pick up so much stuff that are buggy or alter the system behavior. The worse is that there is no release notes. I have asked for the release notes since a month ago and yet it is not here.
And I notice you make patches without incrementing minor version # and they all call 5.2. So when one says 5.2, you have no idea which one he's talking about. You should at least make it 5.21 or 5.22...etc Process control needs to be better.