In the last update, “Custom chords now show ‘Custom’ as borrowed chord option” is listed under bugfixes. Unfortunately, there is now a bug where “Custom” is being shown for many chords that are not borrowed.
Consider The Imperial March by John Williams, where every i chord is listed as “Custom”.
It doesn’t always do it though: Ladyfingers by Herb Alpert just lists “N/A” for all in-scale chords.
Sometimes it is a mix. In the bridge from Komm Susser Todd by Shiro Sagisu, most of the i chords are “N/A”, whereas the ii chords are “Custom”. Neither chords are borrowed.