For good measure, I upgraded to 6.1.4, the same level my indexers were on. I realized my license manager was on a 6.0* flavor. Sometimes that inconsistency can caused freaky things so I figured at the least I should fix that.
Then I threw down some btool to check what was up with my license server config.
btool server list --debug | grep -v system
showed me the I had erroneously configured the deployment server to send an app to the license master that contained a definition for the license target! ( [license]'s active_group and master_uri attributes).
After clearing up those shenanigans and restarting, I stopped seeing the error.
So...in my case, my issue was caused by bone-head config by yours truly.
On a side note, this may have caused my license usage to appear dramatically higher than it actually was - which makes sense if it was recursively posting to the license usage as a result of the config loop.,