Hermes - a new cooldown addon

[Paperplate]

It is entirely possible I may have reloaded the UI on one of my slaves around that time.

If you did reloadui, this would definitely have caused it. Briefly explained:

1. Your slave logs back in. It broadcasts a message "Hey! New Sender here!"
2. Receivers get that message and reset their data for that sender (this is why the buttons disappear).
3. The receivers then whisper a message to the sender "Hey, track these spells would ya?"
4. To which the sender would get that message and eventually send out an update for those spells if it has them.

In anything, something about step 4 may have gone awry in your case. It should have updated eventually.

I might consider eliminating step 2, not that it would help you. Just thinking out loud.

I just read your second post, that was a very entertaining read!! Thanks for taking the time to indulge me there. You're actually kind og lucky as it's pure luck that the strata level for the buttons on Hermes are higher than Bartender. That was the first thing I thought of when I saw your most recent screenshot Anyway, very information for me not just in how Hermes is helpful but in understanding just what it is that you are doing.