C:A0C0 and C:A1C1, amp solution bumps, possibly as early as Jan 07, persists through B, BnA, A
uncertain if same cause in 3bit and 8bit. examples of both are here:
/lustre/aoc/projects/srdp/problem_data/ea01_AC/
8bit:
3bit:
below, black is ea01 (brown is the typical ea17 issue)
