I fiddled around a little bit. Maybe a thread in the bug-section would be appropriate? For now i'll just share my little insights here:
Uller C
-standard-configuration (after I deleted my XML) only says "5 weapons in total", although all 6 (respectively 7) are listed -> standard-config has an error
-I set groups; this should happen (the lines refer to the MGuns, used only in group 2):
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_0.0" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_0.ActiveCount" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_1.0" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_1.ActiveCount" value="1"/>
but this happens, every single time the file is saved (regardless of whether i used an Uller or not)
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_0.0" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_0.1" value="2"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_0.ActiveCount" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_1.0" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_1.1" value="1"/>
<Attr name="Multiplayer.MWLL.FireGroup.CL_Uller_Mech_C.Weapon_1.ActiveCount" value="1"/>
two useless lines, they do not cause any problems (but there seems to be something wrong somewhere else)
-XML seems to be saved after a profile was loaded, after a map was loaded, after a death, and probably at other points (leaving the map when still alive or even crashing, i guess)
-"<Attr name="Moo.Meh" value="0"/> " does not seem to cause trouble and is not included in the next save (so it is "touched")
PS: What kind of line would even cause the weapon-groups to reset? Have not found any of those yet. (Ok, maybe it is not an error while saving, but has to do with the following text.)
EDIT: Something very interesting just happened!
After playing on an empty server for about half an hour with only three assets in use (Uller C, Uller B, Sulla Prime) i joined a populated server. I crashed my plane twice, nothing of interest happened. Then i left the server and my file got saved again. Two formerly unused assets were written: The Hollander B and the Bushwacker D. I did watch a Bushwacker D for a while ingame. Maybe i also watched a Hollander B (do not remember it, but i'll double check), the game had only run a couple of minutes, so that would be very likely.
In short: It seems that the weapon-settings of assets I merely watch (follow while spectating, that is) are written to my configuration file. I will have to find out whether my own settings can be overwritten that way.
PPS: Is the XML read in while the game is running? Or is it only read in once while the profile is being loaded? The latter one seems to be the case because that Bushwacker D showed up again and again, no matter how often i set it back to its standards (i copied and pasted the standard XML-part, deleting the unwanted settings).
Another result:
It seems that only the assets with wrong standard-configurations are written while i watch them (until now i only noticed wrong amounts of weapons, the rest is just too complicated to get it at a glance). My settings for the Uller Prime for example were not overwritten while watching somebody else pilot one, they already were correct. But if I introduce some kind of mistake into the settings, maybe they will be overwritten by watching somebody else pilot an Uller Prime because the software sees the erroneous settings and replaces them with the standards?
If so, the error-correction in conjunction with the errors that are made during saving the configurations (mentioned the always wrong Uller C before, maybe that already qualifies as an error) would cause personal settings to reset.
I'll continue testing this, maybe it is nonsense.
PP...PS: Sorry for getting that far off topic. I am just not in the mood to find a more fitting place for this, somebody will take care of it.