Having the text as negative space on dark is still perceptually different to having it on a transparent background (which is perceived as negative space). This is enough to make it feel unbalanced.

See here: https://i.imgur.com/uW4TGX2.png

Purely subjective. I personally see no difference in the balance, and either way, "balanced" doesn't mean correct.

Thank You! This is enough to illustrate the problem. It would have been fine if they had kept the black as background colour.