Crash when ungrouping mask in isolation mode

pentool

App crashes when trying to ungroup a mask in isolation mode.

Create a shape. This will be the one we'll mask.
Create a few more other shapes (possibly smaller ones) and group them. This will be the mask.
Cut this grouped mask (Edit > Cut)
Select the shape that you want to mask.
Bring up the Transparency Panel and in the Mask dropdown select the Drawing option. You will enter isolation mode.
Paste the grouped mask into the isolated mode.
Right click the group and select Ungroup. Crash.

VS 1.1.100

b77

@pentool Replicated here.

VectorStyler

@pentool Added this to the backlog.