Anchors in components not propagating properly into composite ligature

I noticed that if a composite ligature consists of n components, and each component has top/bottom anchors, that Glyphs will propagate them as top_n and bottom_n in the exported glyph.

However, if a component has another custom anchor in addition to top/bottom which contains “[Tt]op” in its name which is used by other marks, it will cause the standard behavior mentioned above to bug out.

In my case, the second component in an Arabic ligature has a wideTop anchor, and this causes the top anchor from the first component to disappear from the final exported glyph, so the final ligature ends up with only three: bottom_1, bottom_2, and top_2.

This is easily fixed by renaming the wideTop anchor to anything else without “top” that’s not used in other anchors, but is unexpected behavior.

Edit: using 3.2 (3213)
Edit: the bug has nothing to do with “top” in the custom anchor name, but whether this name is used by other anchors in other glyphs.

can you send me a sample file?

I managed to fix the issue of the disappearing/misnamed top_1 anchor by renaming the custom anchors throughout the font to ijam_wide (ijam and ijamWide throw it off). It’s not obvious why the underscore fixes the issue, and maybe the application should warn of improper custom anchor naming. (I’ve sent the Glyphs file by DM)

I fixed it. Thanks for the file.