I've created multiple machines and they all work. Except one. After placing the last block, it detects the structure (you can see it in the GUI and in the colorchange of the blocks), but a few seconds later it says "none" again in the GUI. Replacing the one block next to the fluid lets it recognize it again, but only for a few seconds like before. I've tested replacing all blocks, just this one block (the orange one in the first screenshot) works to refresh the multiblock.

This block has to be replaced

Detection works

Structure Json (needs Immersive Engineering): https://gist.github.com/TimGoll/0c5a3aa55c651cafe93e92867bc06b95

forge: 14.23.4.2760
MM: 1.9.4

Okay, wow, I found the issue by myself. This one block had still ne nbt info in the json file. After removing it, it worked...
You should consider disabling the automatic writing of NBT data to the JSON file. Maybe a mode switcher for the ingame tool

Problem with that option is that some blocks NEED that NBT data, so a blanket disabling doesn't work. They need to be manually reviewed when using the tool for a reason.