That means your BMS is cutting out, not the controller. The unplug resets the bms.
The CA can set max amps, and lvc for the whole pack. It will not do lvc for each cell like a bms can. You might have one bad cell, or even just one bad connection in the pack causing the sag. Bottom line, look at everything.
What's your max amps on the CA? That may tell you what amps your bms is cutting out at. That spec sheet is the cell, whats the spec on max amps on the bms?
Your battery spec sheet says 200 amps max continuos, 10c , but that does not mean 200 amps without sagging like grannies tits.
Just cruising at 30 mph though, that should not be much amps. Should only pull 10 amps once at 30. But can easily be a lot more getting to that speed. I'm wondering if you are running a false phase wire order, and drawing crazy amps when you try to accelerate or something. If you can't creep real slow up to 30 mph, then something is seriously wrong.
Might try limiting amps on the CA to 15, and see if you can at least reach 30 mph.
200 amps max from a 20 ah cell sounds a bit optimistic, using the rule cut all specs in half you'd likely get ok performance at 50 amps max. less than 5c in other words. BTW, 5c is f ing huge for many types of cells. I don't know anything about what you have, but it sounds like a lot! You might have some really optimistic specs there, like, specs for something, but not what you have.