Wildwood Rucksack and guild stash

It seems that auto association and ctrl+click don't work with Wildwood Rucksack in guild stash

Same for me, works with normal stash, but not guild stash. Sometimes nothing happens and sometimes it stashes something else from the normal inventory.

How to reproduce
1. Specced with Wildwood Rucks, open the Guild Stash.
2. ctrl+click (cmd+click on Mac) on anything in the Rucksack.

Expected behavior
The item clicked on should be moved to the Guild Stash.

Actual behavior
The item clicked on is not moved to the Guild Stash or another similar item from the normal inventory is moved to the Guild Stash instead.