This is a very serious bug because a simple use case leads to a crash in explorer and making very hard to copy and paste files. To reproduce one needs to copy one file from c:\ and paste it to desktop. Then copy one file from the desktop and paste it to c:\. Trying to open the context menu to press paste causes an exception. The other way around causes the same symptom. It is as if changing the place from which you copy causes a corruption that leads to an exception later on.
It may not be apparent that an exception happened but it can be caught reliably either with "set condition * first always" for kdbg or with "!gflag +soe" for windbg.
This is a regression, and a serious one that already happens for some time and it is important to pinpoint which revision caused it.
This is not a regression, we have this ever since we switched to the new shell.