While working on the "remastered" versions of the official / early-LP graphic sets, I noticed a couple of anamolies in the Bubble tileset's pieces.
Specifically:
Terrain 51, the horizontal section of this piece is one pixel thicker than on any other matching pipe piece.
Terrain 55, near the horizontal-diagonal joint, one pixel underneath the pipe is missing.
Should these be fixed? On one hand, this could cause issues with existing content / replays - it's minor changes, in one of the less-frequently-used tilesets, so the impact shouldn't be huge, but it probably won't be zero. But on the other hand, I'm not sure how I feel about leaving such inconsistencies in.
Perhaps one possible approach - fix them, but leave it until next time another change that may break compatibility occurs. This way, the rare level that gets affected by this can be dealt with at the same time as dealing with those, and it's in line with the "if things must be broken, try to break as many of them as possible at the same time rather than heaps of small breaks" approach that was used for the V1.43n-F to V1.47n upgrade.