Brake pedal sticks to floor today 💣

[Zombie killer]

Today during my last 2 autoX runs the brake pedal would stick to the floor and lock down the brake calipers to a dead ass stop. It would only happen during a hard full ABS braking zone. First time was at a 180 sweeper and when I came in hot and stabbed the brake pedal it stuck on the floor and stopped me dead in my tracks. It took a few quick stabs on the pedal to get it to release. Finished the run with no problem. Checked everything I could in grid and thought maybe just a fluke. Next run went good with no issues except when I passed by finish and used another full abs to stop and it went to floor again and stuck. This time it seems that stabbing the brake 6-8 times to release didn't work. I shut off car and re fired it back up and pushed the pedal and it quickly released. I did a quick google search and checked C5 but I didn't see much of anything of it anywhere. So I am curious if anybody has personally heard of this happening and can share any insight as I plan on pulling off the wheels and checking the entire system out but could use suggestions from someone that has knowledge of this happening on a 5th Gen.

For what it's worth, I am running mogul 600 and last flush/bleed was just around March. I am running the stock SS Brembos and stainless steel lines. There were NO check engine or abs lights, or other warnings on the dash. I want to think it's purely mechanical and possibly in the master cylinder or booster Now this may be a coincidence, maybe not, but my car started puffing a good deal of pure white smoke at the starting line today during the dead stop WOT starts , but no other place. Checked master cylinder and it doesn't appear to be low of brake fluid. The white smoke and sticking pedal seems maybe a booster problem ???