Yale Romanisation Feedback

I'm using Pleco flashcards to test my pronunciation using Cantonese Yale Romanisation.

I'm finding some strange issues with the Yale Romanisation. I'll list them here on this thread for your feedback.

The Yale Romanisation is listed as ǹgh4 on the flash card. But when I enter ǹgh4 in the answer box it states it's incorrect. I need to enter ǹg4 to get the card scored as correct.

Strangely, in a list of flashcards (like in an Organize Cards list) the flashcard is listed as ǹghú. In the dictionary entry, the Yale Romanisation is listed as ǹgh±.

I think the correct romanisation is ǹgh4, but not sure why it's showing up differently in different places within the app.