The only reliable way to catch this (It's a Blizzard problem, unless they've recently fixed this...) is to delay for a second or so, because the it's seemingly random if it counts the one you just got or not.
Just as I don't correct for it now, it's sometimes wrong, if I correct for it (Current+looted#), it'll be sometimes wrong too, if polled immediately.
If there is a similar addon that never errs, I'd like to know how it's done, so I can fix it.
I wonder how addons like Possessions keep accurate count of things. Probably they just delay checking since they don't actively notify you of changes.
I wonder if it would be possible to cache the number of each item in the player's bags at login and then manually add to the counts based on parses of the loot events in the chat log or something, rather than re-polling the contents of the player's bags (I think that's how it does it now maybe?). It shouldn't be too memory-intensive to maintain a list of ~100 itemIDs with counts of how many of each are in the player's bags.
Yeah I finally gave in and am using teksLoot (or whatever it's called) and Butsu. I miss the loot monitor most of all; it'd be great if someone could make something similar as a standalone addon or something.
Got the conflict issue again with some other addons, so I grabbed the branch version. It doesn't cause any problems, but I know I'm going to miss XLootMonitor a *lot*.
I'm also going to miss XLootGroup, because I hear that teksLoot doesn't let you adjust the scale.
Edit: I get errors or no loot frame if I turn off either the frame or item border coloring options in the XLoot-1.0 branch version. Also, the loot frame doesn't appear the first time, which I see you mentioned as a known issue, but it's pretty bad imo :p
Also, none of the settings take effect while the loot frame is active, which makes it hard to configure.
Edit 2: Happy with teksloot+Butsu for now. Keeping an eye on XLoot1.0 though.
After reading what you said about RBM, I tried turning it off and turning Loggerhead and XLoot on, and that made the problem go away too. This means that there's some kind of 3-way conflict going on, as I can run any two of the three addons (RBM, XLoot, LoggerHead) without issues, but all 3 causes massive breakage.
Yes, the auto pass text shows up in the monitor, at least sometimes. Maybe it's unintentional - maybe XLoot Monitor shows text that it knows is loot-related but doesn't know how to interpret?
It usually happens when the errors would occur, but I haven't been in an auto-pass situation since the latest fix went in, so maybe the fix will change the way it shows up (or doesn't) in Monitor as well?