+1 what he said, you may briefly burp it but your dash will light red and power will cut almost immediately to stop that spin. I have mine set I believe it's 3, midway, at times I may hop the front wheel a little bit, but as soon as the bike even thinks im getting ready to do a wheelie, OR if I 'chirp' the back wheel, it immediately cuts down the power and acceleration until it feels the roads are normal again.
If your tire is worn out and slick, when dry and on a cleaner / nicer road, it will get great traction. That is why they use slicks on the race track. Now throw in a little sand, a little grit, a little moisture on the road and it'll start sliding on a wad of spit, and your T/C and ABS will have a field day with you. Temperature dropping 10 degrees can play a huge part in your TC and / or ABS kicking in as well, as cold tires slide a lot more. TRUST ME, I have an almost soiled pair of pants I can send you for verification that tires will slide a LOT easier when cold !!
The job of ABS / TC is to keep you safe, and there are a lot of things that can affect it and set it off. It's hard to tell you, ok THIS caused your problem w/o being there at the time to see all what was going on, as it could have been a combo of things that set it off too.
As for the regen staying off, and you having to cycle power. There is nothing that I can think of that would cause your bike to do that purposely, EXCEPT for you having a freshly charged battery that was over 95 percent full. It may have just been a coincidence.
If your battery is above 95 percent charged, your regen may be turned off, or severely dampened because there is nowhere for it to put the power from the regen, so you must use brakes instead.
Aaron