Alternate bracket layer eliminates ligature feature?

I have ‘non-overlapping-/f’ as an alternate bracket layer for the heavier weight. However, this eliminates the ligature substitute for the heavier weights (in most applications) which uses the same alternate layer settings. Is this a bug or a low-supported attribute for most apps?

Technically, a bracket layer is a different glyph.

Is that a variable font?

Sorry, I forgot to mention. Yes, it is a variable font.

And what feature do you use for the feature variations?

Just the standard optical size (opsz) and weight (wght).

Can you send me the .glyphs file?

I’ll send it now.

As far as I can see, it works as expected. Can you show some examples what you expect and what happens. And where are you testing?

Font Goggles show the expected result for alternate bracket layers and ligature substitution.

InDesign shows the expected result for alternate bracket layers but the ligature feature fails when switching to the alternate layers.

Any thoughts on whether this is a bug or a low-supported attribute for most apps?

When it works in Font Goggle and webbrowerse but not in Adobe apps, it is most likely an Adobe bug.