A Debian user reported the following:

"I created a simple diagram for a database model, next I grouped some
objects (a box, some text and lines) to conveniently move them around
and connect with lines. But after I needed to do some changes to a
grouped entity, the program crashed after performing the ungroup
operation. It keeps doing that in that document, although not always.
The easiest way I found to reproduce this bug is to do something else
before ungrouping, add some items, possibly turn on the 'snap to grid'
option, then start ungrouping. It crashes around the 2nd or 3rd ungroup
operation."

I could reproduce it this way:

1. select the "INSTYTUTY" box and the arrow left of it.
2. group (Ctrl+G)
3. ungroup (Shift+Ctrl+G)
4. goto 2.

After ~10 iterations a segfault occurs for me.