Hey there nysci. Thanks for the note here – I just tried to recreate this and was unable to. I followed these steps:
1. Created an event and added a tag called “animals.” Published that event, viewed it on the frontend and confirmed that the tag showed on the individual event entry (and that the event showed up on the tag page).
2. Went back to the entry, removed the “animals” tag and resaved. The tag no longer appeared on the frontend single event entry, and the event no longer showed under the tag loop on the frontend either.
I notice you’re still on plugin version 3.2.1 and WordPress 3.6.1; those are both quite a few releases behind. Any reason you haven’t updated to the latest codebase? Based on my testing it seems like it’d go a good way towards getting this fixed. Let me know if you’re able to give that a shot.