R3.1.1 x64, Windows 10
For my part, I checked the bugs where I was involved in the past:
>- Notes placed on the last line in each pattern, do not appear in Matrix Editor?
This seems to work correctly. Tested even with 512 lines per pattern.
>- Tracks are swapped around when cloning a group:
Group cloning now clones clues and child groups and its properties correctly, by dragging the parent group with CTRL. But for some reason, there is still something that does not work properly with "Collapse/Expand Group". To verify this, create a parent group with several random child groups, and within those groups add multiple child tracks. Then collapse several groups randomly and clone the parent group. Final cloning does not return the same order of collapsed groups.
On the other hand, to clone a group, it is only possible by pressing CTRL and dragging with the mouse the desired group.
I think it is not possible to assign a keyboard command for "duplicate group", nor does an option appear in the group drop-down menu, something like Group/Duplicate, Group/Duplicate (incl. Patterns), same as the track menu.
After trying other things, I found this:
Basically, I created a group with a child track. Then I've cloned the group. Finally I have dragged the cloned group into the first group, and the error appears. After this error, Renoise 3.1.1 automatically closes. This error has appeared after I have been manipulating groups and tracks, cloning, creating, deleting, collapsing/expanding the tracks and groups randomly. Maybe it's related. I do not think he has manipulated more than 40 tracks/groups.