Metrics Key is acting strange

I am sharing the LSB of El-cy with Lje-cy
LSB of El-cy is Zero but somehow the LSB of Lje-cy refuses to settle at Zero
every time I Update Metrics it goes to either 1 or -1

trying to figure out what is going on, I realise that the same file is open twice in the same version of Glyphs. So in the dock I had two Glyphs 3 open. How is that possible?
I closed all, restarted with just one file in just one version of Glyphs and all of sudden it worked :person_shrugging: