So far I have played 5.12 3 times. And during each of these times there was at least 1 moment where I encountered this issue, be it with different symptoms.

The first time it happened I was in a server with only Spyro, who was spectating. Then after some minutes I suddenly see ammo being shot at me by an invisible player. I decide to rejoin only to see that 3 players had joined and one of them had spectated off. My game seemed to have failed notifying me of their presence in any way, except for their bullets. Since this caught me completely by surprise I have no other evidence of this than the chatlog:

(loaded script module spawntimes.mut)
(loaded script module uppercut.mut)
(loaded script module weaponbinds.mut)
(loaded script module zd.mut)
[18:36:38] Console: Welcome to Zeal Duels 1!
[18:36:41] A level guide is available. Press F1 to view.
[18:37:10] [CDF]Spyro joined the game
[18:37:13] [CDF]MS: hi
[18:37:15] >> Attempting to no longer spectate...
[18:37:15] Console: [CDF]MS is no longer SPECTATING
[18:37:16] [CDF]Spyro: Hi
[18:37:17] >> Attempting to login...
[18:37:17] Console: >> [CDF]MS has logged in (Player)
[18:37:20] Console: >> [CDF]Spyro has logged in (Player)
[18:38:23] [CDF]Spyro: I'm about to get my dinner, so I need to eat rn
[18:38:27] [CDF]MS: okay
[18:38:31] [CDF]MS: just stay here so we can get players
[18:38:33] [CDF]MS: enjoy!
[18:45:55] [CDF]MS: wtf
** End of Log [[Friday, August 25, 2023 at 18:45:59]] *

[[Friday, August 25, 2023 at 18:46:02]]
Current level: "FTL Starship" - ezstar.j2l
Game Mode: CTF
(loaded script module ezstar.j2as)
(loaded script module guide.mut)
(loaded script module h.mut)
(loaded script module leaderboard.mut)
(loaded script module mute.mut)
(loaded script module nodetail.mut)
(loaded script module randomlevel.mut)
(loaded script module spawntimes.mut)
(loaded script module uppercut.mut)
(loaded script module weaponbinds.mut)
(loaded script module zd.mut)
[18:46:02] Console: Welcome to Zeal Duels 1!
[18:46:04] [CDF]MS: wtf
[18:46:06] A level guide is available. Press F1 to view.
[18:46:07] [CDF]MS: new bug???
[18:46:09] A7med: game physics?
[18:46:09] [rig]arianator: sus
[18:46:12] A7med: wb
[18:46:14] [CDF]MS: ty
[18:46:16] [CDF]MS: on my screen
[18:46:18] [CDF]MS: I was alone
[18:46:20] [CDF]MS: only spyro spectating
[18:46:23] [CDF]MS: then I saw ammo
[18:46:26] [CDF]MS: from an invisible player
[18:46:29] [CDF]MS: thats why I rejoined
[18:46:38] >> Attempting to login...
[18:46:39] A7med: seems like a new bug

The second time I was in the middle of a game. They decided to stop the game, however for me it was still started. I was voicechatting with a7med at the time, so it was clear I wasn't disconnecting. I could still move while others on my screen didn't, I have no idea what their perception of me was. Also notice that on the screen, Chipsy has a * behind her name, indicating that she had the flag, however on my screen it is clearly on enemy base.

The third time we were playing a 5v5. Making it quite hard to notice everything thats going on, bugs included. However, if I remember correctly, I had just passed an opponent having the flag, when I saw a7med, who had a * behind his name yet was not carrying a physical flag as you can see on the screenshot. Also notice here that I am carrying the flag, yet Kev has the * behind his name. I can remember saying: 'I was quite sure I just had the flag', but do not remember if this was also at this moment or another.


So we have 3 different situations here, the symptoms being different, especially of the first situation. Do they have the same cause though? And can this cause be reverted by undoing the changes that caused it until it can be introduced in a bugfree manner?

Here is another example of multiple delayed&missing messages (and desync???): https://imgur.com/fIm0JXe
Ms roasts kev, but theres no message that kev lost flag and kev keeps the yellow flag star at his nickname, even after a7med recaptures. Also spyro makes the score but keeps the yellow star at his nick. MS captures, gets killed immediately by zolika but there?s again no flagloss message and yellow star is still at spyro?s nickname. Afterwards, spyro recaptures, loses flag again without flagloss message and lina recaptures, but yellow flag star is still with spyro. Then suddenly some of the missing flagloss messages appear on the screen together, eventho MS didnt even have the flag anymore. That?s when the yellow stars get updated finally in the playerlist.
U can watch the scene here at video timer 1:21:15-1:21:35: https://www.youtube.com/watch?v=lsdYI2aE8I0&t=4833s
This was in pxi intervall testbuild but with the exact settings which 5.12 uses now (/bulletvictim off and 0/0). And it fits to what MS described before.