Underline action in lyrics reverses Bold action (on the same syllable)

When writing lyrics in Bold, if you underline some of the letters and save, it looks good [[ See Sample 1 attached ]].
After exiting the file, and trying to open it again, the Bold is gone for all the syllables that contain at least one underlined letter [[ See Sample 2 attached ]]. No issue with Bold only, or with underline only, it's just the mix of the two. This is consistent across all files and scores in Musescore4 (whether written in Musescore4 or copied from Musescore3).
Interestingly, if you unbold only the letter that is underlined, the rest of the syllable letters stay in Bold after exiting and reopening of the file [[ See Sample 3 attached]].