The Havocs are rapidly becoming a thorn in my side... while one is managable as long as I prioritize, I've come across issues in random missions where three can cause a stun-lock that persists--while I have full suppression.
If they ripple-fire, and I'm hit with the knockdown attack two or more times in a quick (seems to be 1 second) period, I am locked out of all controls for between 20 seconds and a full minute and often it causes my DR to be completely ignored as well. I mean all controls--I can't even open the esc key menu. It also resets all of my cooldowns (frustrating when you're trying to jump-pack away) and keeps them locked for that entire period--IE, a 10 second cooldown will reset and not count back until after the 20-60 second lockdown period has passed.
After that, everything continues as normal, I simply can't interact with the game at all. Enemies continue to attack, damage me, etc... the game itself doesn't lock up, just player input. It's maddening in solo maps, because I can handle CR1 content just fine until I hit a room with 3+ havocs. If I manage my cooldowns properly, I can even handle most elites just fine solo.
Since I'm reasonably sure this isn't working as intended, I'm posting a report, as the lack of diminishing returns on stun means that I can get stuck spending up to three minutes unable to do anything until I finally have my health chipped away enough to die outright--each time finally restoring control only to have another rapidly moving insta-turn missile (wat, that's not how bolters work!) catch me just as I move/jump-pack away and the whole process starts over again. And Emperor help me if something with a flamer shows up, then I'm just stuck in place watching my Suppression and HP vanish through the DR (if I'm lucky) or just evaporate instantly (when I'm not and it just turns my DR off).
TL;DR: 3+ havocs disable DR and player input including esc key menu for up to a minute while at full suppression if they hit within about a second of the last havoc's hit.