For example, S2B_MSIL1C_20240801T214809_N0511_R043_T02LLK_20240802T003226.SAFE. Fmask shows no warning (maybe they're disabled by default), but it must be going through the code path at https://github.com/GERSL/Fmask/blob/master/GRIDobj2geotiff.m#L57 if it's writing a .tfw.
Most software can still read the world files, but the bigger issue is that these are also missing their CRS (understandably), so they're unusable without re-setting it.
Finally, the output also has an inverted grayscale color table by default, which is not really a problem but can be confusing to some users.