WIP: [ATR-22325][ATR-22597] Remove trigger thinning for R2 data (not thread safe)

For reasons described more on [ATR-22325], R2 trigger navigation thinning is not thread safe. Nor is it trivial to make it thread safe.

As this format is soon to be deprecated in favour of R2->R3 format-shifted navigation, I instead here just remove the unsafe calls.