When an AI-controlled Tempest activates its system to change the terminator drone's roaming orders, it drops its shields.
How to reproduce-
• Fit a Tempest with 1x AM blaster in the left slot, 1x Heavy Burst Laser in the right slot, 10x vents, 1x capacitor, hardened shields, extended shields, and resistant flux conduits.
• Run a simulation, deploy the Heavy Support Dominator. (I use the take 50% damage option usually, just fyi)
• At some point you'll hear the chirping of the Tempest activating its system while under fire and you will see it drop its shields.
That seems to reproduce it pretty reliably. In that fight, you may also see the Tempest drop its shields while under fire to direct it towards incoming Pilums (which can be kind of annoying), but isn't really an issue.