nullius-mirror-flotation-cell-2 is not a correct mirror of nullius-flotation-cell-2
https://prnt.sc/aOGPofCLsCvC
The connections are additionally rotated by 90°.

The distillery only has inputs/outputs on 2 parallel sides, so it can be flipped along the perpendicular axis. The flotation cell is different because it has inputs/outputs on all 4 sides. You're envisioning that it should be flipped twice, once along the horizontal axis, and once along the vertical axis. It is actually flipped along a single axis, the diagonal one along the corner between the 2 inputs and the corner between the 2 outputs.

Your interpretation might be a little easier to work with, though it's complicated to change it retroactively without breaking existing factories by rotating all the buildings 90 degrees.

yes I already thought that it can not be corrected afterwards. I had already built the 90° turn as workaround into the BlueprintExtensions There were a few other mods from the pack that required special handling. I hope I have found all...