Kerning works intermittently or selectively

Hello, dear support team!

Working on my current font project and testing it in various applications (MS Word, Photoshop, Illustrator, etc.) I’m facing with a problem when Pair Adjustment feature works intermittently or selectively.
Moreover, with the same glyphs, it may or may not work. I noticed that sometimes the feature “turns on” only after re-typing the required combination of characters immediately after the first one.

You can see this issue on the screenshot:
15-03-2023 195411.jpg
Unfortunately, I could not find a pattern according to which the feature turns off or turns on spontaneously.
Unless, as you can see in the screenshot, most often it does not work at the beginning of the line. But not always — failures happen or do not happen even when characters are already typed in front of them.

Kerning and other options are enabled in the software settings. The values of second glyphs in Pair Adjustment lookup aren’t changed.

I tried to check the OpenType code for mistakes, editing and break classes to avoid conflicts, decreasing the Pair Adjustments conditions number, but the problem remains. May be you can help?

Thank you!!

I’ve found such a post made a few years ago — OpenType Layout Feature Support Differences - (Complex) Shaping Engine

May be my problem is something like?

Does the font work any better in LibreOffice?

I am not sure if vertical offsets are fully supported with horizontal writing.

Thanks for your response, friends!

Mm, I didn’t tested the font in LibreOffice yet, but it’s critical important this font (in fact, these are two similar fonts) work at least in the most used software like Word, Illustrator, Photoshop, etc.


Oh, I didn’t think about that. In general, of course, it would be cool if the features to work more predictably and it would be clear on what it depends that in some cases they work, and in others they are missed.