I just took a critical skirmish in rhamus b13.
The shields of the queen were slowly discharging when I entered the sector. It seems a bit like what used to happen with the leviathan after killing a couple of queens.

There were 6 bastions in serco space. Usually shields are pretty weak if there are lots of queens.
Ecka was doing skirmishes in the same system at the time ..maybe that triggered something to make it drop below zero.

All the other queens were normal.

Hmm, odd things have been happening, Running through hs missions then the crits vanish supports the observations of Mr S . Doesn't seem to affect the central queen or levi shield strength though .

I should have investigated this before the release/restart last night. Seems fine now, but maybe I can get something from the logs. Let me know if you encounter it again.