After doing a lot more research on ICE MODE, it isn't a brake booster issue.
It seems to happen on multiple OEM ABS modules when used in track days / racing.
A common tigger seems to be multiple small bumps going into a corner.
Here is a post from Travisjb way back in 2012:
I just spoke with Bosch and with the head of their major west coast distributor
Not going to quote anyone directly but basically the theories discussed in this thread are correct. The DOT approved versions of Bosch ABS induce ice mode when the wheel rate sensors detect variation across the four sensors. I am not clear if it is front/rear overall or any one wheel or both, nor did I find out what % difference the computer looks for nor timing involved in the algorithms... but it is a safety mode designed to help in the majority of street situations... hard to blame them for that.
Link to full text:
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Ice mode solution?)
Too bad... For a moment I thought "just maybe"!!