What happens is a few things, same behavior on both devices

When you open mail, and mail loads - if you go to click an email to open, or mark a single email or group of emails as junk, or even mark a single email to move to a sub folder in the inbox, the email crashes and takes you back to device home screen. Happens about 15-20 times on an average day.

You then need to reopen email and hope it doesn't do the same thing again.

Also when going to mark an email and move to sub folder, often the sub folders fail to load and are not shown. Closing out email and reopening, sometimes have to do it multiple times, restores them.

No error messages ever appear

There is no way to replicate or prevent the issue - sometimes it happens and sometimes it doesn't. But being that I use these devices for 80-90% of my work, it's very clumsy and a big source of time wasted and frustration