bug in instruments.xml parsing (Alto voice always shows as A. Bu.)

For a while now I've noticed that for some reason, under voices, the alto voice always shows by default as "A. Bu.", while Sopran, Tenor, etc., were all shown properly.
This was before I found out about instruments.xml
When adding A. Bu. to the score, its Name on main score would be A. Bu. and its Abbreviated name would be A..
lately I've been playing around with instruments.xml, and so I've looked for "A. Bu.". It turns out that this only appears as the shortname for Alto Bugle (which makes sense), while alto has trackname & longname Alto, and shortname A..

This is the same as in the default instruments.xml file that comes with Musescore 4, but just to be sure, here it is, as it appears in my file:
(uh, I copied the lines from instruments.xml as is in here, but the forum mangles anything within angle brackets.
it's literally what's under Instrument id="alto")

As a test I've tried changing trankname, longname, and shortname.
When I change these parameters for Instrument id="mezzo-soprano" I get exactly what I expect, mezzo texts change in MS4.
But when I change these parameters for Instrument id="alto", it has no effect.
The kicker is that even if I go to Instrument id="alto-bugle", which has the only appearance of the text "A. Bu." in the whole file, and change this parameter, the alto voice text still stays the same. alto bugle does change though, which is at least reassureing.

Where does MS4 bring the text "A. Bu." from, and why does it apply to the alto voice instrument?
Does this bug apply to any other instrument I didn't happen upon?
Can I fix this locally, or is this a bug in the software?

Thanks,
Ofir