I'm experiencing the following behavior. If a process contains both Classic and Modern forms, and I set a theme with a header logo on a Classic form, then set the same theme on a Modern form, and save both to the repository, the Classic form shows up fine but the Modern one has the logo missing as seen below.

If I go back into the Modern form, go to the theme, and without actually changing anything save the theme under a different name, and leave the Classic form the same, suddenly the Modern form saves with the logo.

Are themes not supposed to be shared between Classic and Modern forms?