I thought that the incompatibilty triangle was only showing when there were instances that were trying to interpolate between involved masters.
To explain what I mean. I have a file with 4 masters and I am actually using only the 3 (let’s say 100, 400,900) to work and the 4th (1000) as some kind of reference. I have some instances that are in the range from 100 to 900. I get the red triangle that points to interpolation issues in the Font View (as well as the red line in Edit View) in all my glyphs even though the 3 working masters are compatible and only the 4th reference master is incompatible. I might be mistaken but I remember that in previous versions there was no report of interpolation issues as long as a master was not involved in any interpolation. Am I wrong?