Which version of AdiButtonAuras are you using (enter the exact version number here)?

2.0.21

How did you install the addon (twitch client/manually)?

Twitch

If using the twitch client, what type of release did you install (alpha/beta/release)?

Release

Which type of installation did you choose (nolib/normal)?

Unchecked "Install Libraries Separately"

Warrior Battle Shout Rule "Show the number of group members missing Battle Shout" shows raid numbers after leaving raid group.

I have the following settings for Battle Shout:

Show missing: Show Flash
Show missing threshold: 0
Rules: Show the number of group member missing Battle Shout: Checked

If I'm in a raid group, and there are members without Battle Shout, it of course has a number there (say, 16, for example).
Then, after leaving the Raid Group, the number shown is still 16.
If I cast Battle Shout to try to clear this number, it still shows 16.

So, AdiButtonAuras should probably reset, clear, or re-update the missing group members number upon group changes (including Instance Groups and regular Party groups).

If I cast Battle Shout to try to clear this number, it still shows 16.

I pushed some changes to address this, however the quoted statement seems strange. Could you please test with version 2.0.22 and share your results?

I was finally able to try this out today.
Even with 2.0.22, the issue persists; the group member number count (of those missing Battle Shout) still shows the same number after leaving a raid group.
In Legion, this wasn't an issue, incidentally.

There were no group buffs in Legion :) This is strange however, I'll need some time to investigate.

While I found a bug with the rule (it counts party and raid pets too), I can't confirm that the counter does not refresh when you exit a party. It displays 1 if you are missing the buff even when you are not in a group and updates accordingly when players leave or join. Maybe you have a custom rule there or something.

Well, I meant during the 8.0 pre-patch timeframe. It worked during that timeframe and broke when BFA went live.

Regarding your repro, were you in a raid group where it showed the missing buffs, THEN left the group and it showed 1 instead of the raid number?

I tried to reproduce with an LFG dungeon group. The number of missing buffs updated correctly both when other players and I joined/left. I don't see why a raid should be any different unless GROUP_ROSTER_UPDATE does not fire when you leave a raid (this is the event ABA uses to update group units).

I haven't tried your settings though (missing flash and missing threshold) but those should be irrelevant for the count. I'll try it out just in case.

Edit: Please check again if you have other rules enabled for Battle Shout.

Can you try to repro by leaving an actual raid group (not just a 5-man group)? The issue manifests when leaving a raid group, such as via world quest group finder for a world boss.

Is GROUP_ROSTER_UPDATE a Blizzard function or ABA custom function?

If you need more info from me, (addons list or whatever) please tell me.

EDIT: The only active Battle Shout rule is the default one "Show the number of group member missing Battle Shout." I have no User Rules applied on anything (blank User rules page).

EDIT 2: Reloading the UI clears the erroneous count.

Tested in a raid too, can't reproduce.

What are the next steps for troubleshooting?

TBH I don't have any idea what may be causing this. I don't see how other addons may be interfering, but you could try to reproduce it with all other addons disabled. You may also close the game and wipe ABA's settings (simply move \WTF\Account<your account name>\SavedVariables\AdiButtonAuras.lua to another folder) to check if this is causing it. Other than that I'm out of guesses.

Have you tried disabling the rule to see if something else displays something on that button?

I tried renaming my AdiBurttonAuras.lua in saved variables so that it re-generates it, but the issue still persists.... :/

Another thing I noticed is that the count doesn't seem to consider combat pets like hunter and warlock pets.

Disabling the rule does not show any group count numbers. The only number being displayed is the cooldown timer.

Additionally, even with the Rule disabled, having the spell set to Show missing = Show flash is erroneously flashing even if I have the buff, with 50+ minutes remaining even. This flash border appears after the 15-second cooldown timer completes.

Yeah, disabling all rules does not disable the button which is kind of strange maybe. But this is unrelated to this issue.

You have not by any chance modified your copy of ABA, have you?

I have not modified the LUA code of my copy of ABA, if that's what you mean.
At most, the modifications i've made are settings such as flash when missing, etc.

Here's the troubleshooting steps I've done today:

1. I've disabled all add-ons except AdiButtonAuras and AdiButtonAuras - Configuration.
2. Checked (enabled) the "Show the number of group members missing Battle Shout" rule.
3. Joined a raid (world boss Matriarch Ji'arak).
4. Cast Battle Shout. It displays a non zero number.
5. Leave the raid.
6. Issue persists: The same non-zero number is still displayed.

My next troubleshooting steps I've done are to completely manually delete both AdiButtonAura addon folders, and all AdiButtonAuras saved variables, and to re-install via Twitch.

We'll see if the issue still persists...

Thanks a lot for your persistence. Btw could you confirm that the buff applied by Battle Shout has the spell id 6673?

I'm sad to report that the bug I'm experiencing still persists, and it's not limited to raid groups.

I was in a group of 4. Casted Battle Shout (Spell ID 6673, confirmed), it showed 2. I left the group. The number immediately changed to 4, even though I was alone.