[mmu]

I have a kindle paperwhite 2021. I have been converting several epub to azw3 using Calibre and noticed that all the new azw3 books loaded in kindle ends up resetting to 'publisher font' setting on kindle. But the font on font settings in kindle, still point to Helvetica (which I have made default for all books).
I had to manually change the font to Helvetica or my saved theme again, every time I open a new book. This looks like a bug because 'publisher font' is not selected but still the font is changed from Helvetica.
Is this a known bug with azw3 formats and the new kindle paperwhite? I did not have this issue with my older 2016 kindle.
Is there a way to disable loading of this publisher font when converting using Calibre? I have already removed all my CSS styling such as fonts during filter styles in conversion and also made sure there are no embedded fonts using run checks option which gives me no fonts at all.