Hi,
The objects [key], [keyup] and [keyname] can't be used in a multi-instance context. The are bound to **static** symbols generated in the setup() methods so it breaks the multi-instance support. I added a commit to fix this on this Github PR: https://github.com/pure-data/pure-data/pull/288.The PR already integrated the fix for the stack count issue. I hope it's fine for you if I make all my multi-instance and multi-thread corrections in this issue, otherwise I can split everything in separate PR.
Cheers,
Pierre