It's quite instructive looking at fonts with problems! I see the same mistakes when Latin-accustomed designers tackle Southeast Asian scripts. Here are the main ones...

1. In Latin, we make the arches of m a bit narrower than in n, but this is not a universal principle! As a rule don't assume this applies to other scripts. Don't start condensing letters with more bowls in Burmese or Thai. Use the same element...

...but be aware of exceptions! Better to take your lead from locally-designed fonts, where native designers know the proportions. There's no substitute for careful examination of plenty of other designs...

In Latin, though we may not see it, we balance shapes towards the baseline. The bottom half of B, 3, S or H is larger than the top half, as we see when flipping these letters. This is not a universal rule!

This logic doesn't apply to Thai and Burmese; remember these derive from Indian scripts where there isn't so much a baseline as a headline, from which letters hang. Knowing the history of the letters explains so much.