I'm going to guess that you will be able to replicate this issue and fix in a coming release (fingers crossed).
In support system admin with a few tickets, would like to close some with the bulk actions dropdown. The screen refreshes and the ticket status is unchanged.
Bulk delete and bulk open work fine.
The twist on this is, that once you have closed a ticket using the one by one method, and reopen it, the bulk close ticket function works fine.
Do tell if you get the same results. I don't believe I have caching on for the admin area or DB for logged in super admin.