Trouble with interpolating smart corners?

Not sure what’s going on. This typeface uses smart corners for every rounded corner. What’s going on here? It’s compatible, and if I delete all corners, and then re add them it sometimes works.

I’ve tidied up my paths and double checked my corners.

Edit: Glyphs has been getting slower and slower as I add more corners/weights. Is this normal?

I just got it to work, by deleted the corner and placing it back. But this seems to be happening randomly, any way to fix this? Am I just using way to many corners?

Probably an incompatibility. Consider running the Propagate Corners script from the mekkablue scripts. It copies the exact same corner/cap setup from the current master to all the other masters.

Will keep that in the back pocket, seems like everything is working perfectly now. Just the preview is sometimes glitched showing missing corners, but on export it’s fine.