I was just wondering if anyone had seen this one; I did the BOS missions, got power armor training, and somewhere along the line (I didn't notice until several levels later) I literally lost nearly all standings to factions. NCR went from idolized to none at all, caesar's legion went from vilified to none at all, etc. Not neutral - no standing, aka not even listed. I reloaded my oldest save and found that I still have correct standings right before completing the BOS missions. Is there a way to fix this problem, other than going back to old save and replaying about a day's worth of game/several levels/emorage at bugs?

AFAICT that's a "cosmetic" bug triggered by switching faction armors. It fixes itself by fiddling with the pip-boy for a bit, your reputation never changed.

Then there's the pip-boy map bug that virtually clears the world map as if you were still 1 minute into the game, or the "bright green screen" effect we already had in F3... Oh well.

If you are "disguised" as a faction member then all non town/city reputations will not be listed and considered neutral.

edit: typo...

When I'm dressed as NCR, the Caesar Legion sees me as neutral! Wtf? That's a bug...

More that they don't see you as being anyone in particular anymore- they just see you as being some guy in NCR armor and therefore shoot at you on sight . The idea is that while disguised, your personal relationship with factions no longer has any meaning and instead they will react to as a member of that faction. That means that although ceasar's legion is shown as neutral to you personally- they'll still shoot you on sight if you're wearing NCR ranger combat armor. They don't bear you any personal or particular malice mind you, but they do know they need to shoot rangers.

but shouldn't the player be vilified by the Legion if he/she is wearing NCR armor?
NCR and the Legion aren't neutral. they are at war with each other.

but if neutral means "everybody who feels like it will shoot you on sight", i might understand why my character is being attacked by the ppl in Sloan, 188 Trading Camp and the Crimson Caravan even though i've never been to the crimson caravan in this play through. (loaded the quicksave i made after my char was attacked after entering the crimson caravan, leaving, killing some raul-guy and being instantly vilified by the NCR, even though my karma is very high.)

Maybe neutral isn't the best word. Basically if removes any positive or negative reputation that you have gained. Obviously the NCR and Legion are at war so you most likely will be attacked on sight wearing an oppositing faction's armor. However, when wearing NCR armor in disguise, NCR members will treat you like a total noobie regardless of your status beforehand. For example the NCR emergency radio will not work.