Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Ah, well I was wondering about licensing, but I saw both your switches had the -S suffix, so you field upgraded just the one?
When you lose the only (or all) switch(es) with the higher licensed features, the stack loses features. IPBase should support routing between VLANs on the same stack (and it appears it does, as it does after you shut/no-shut), but I'm guessing when the stack feature set is reduced, the stack becomes "confused". To me, still sounds like a possible bug, but this is something Cisco might consider a "feature".
A solution might be to run both stack members with the same enabled/licensed features. (I.e. upgrade or downgrade, so your two stacked switches are as "match pair".)
I've run stacks where not all members have the advanced feature set, but I insure that at least two members always do when that feature set is needed.
