if the same entity kills a player/bot(emulating a player perfectly) multiple times there is a chance for it to become completely invisible and un-interactable for players (but other entities can still seemingly can still interact and kill it)

To Reproduce
load up a fabric server without any mods other than "vmp-fabric-mc1.21-0.2.0+beta.7.162-all.jar"
fly to large clearing and set the world spawn in the middle (for easier mob targeting)
run /gamerule spawnRadius 10 to set the spawn radius to 10 to make it clearer
get a new player/bot to join (you can use offline mode if you dont have another account)
run the command:

summon zombie ~ ~ ~ {CanBreakDoors:1,CustomName:'[{"text":"Big Greg","bold":true}]',CustomNameVisible:1b,Health:50,FallFlying:1b,PersistenceRequired:1b,active_effects:[{id:strength,duration:1000000000000000000,amplifier:2,show_particles:0b}],HandItems:[{id:netherite_sword,count:1}],HandDropChances:[1f],ArmorItems:[{id:netherite_boots,count:1},{id:netherite_leggings,count:1},{id:netherite_chestplate,count:1},{id:netherite_helmet,count:1}],ArmorDropChances:[0.99f,1f,1f,1f],attributes:[{id:"generic.follow_range",base:2048f},{id:"generic.attack_knockback",base:1f},{id:"generic.max_health",base:50f}]}

inside of a command block (make sure you have command blocks enabled in server.properties) as it is too long to run in chat
and then run /tick rate 200 to set the server tickrate to 100 (to make player killing a little faster but still not to fast to miss the error) finally run /gamerule doImmediateRespawn true to ensure the player respawns immediately

Expected behavior
after a short while of the player getting killed you should see the player model dosent respawn but you will see the zombie targeting and killing the invisible player and will also get the message in chat however you will not be able to directly interact with this other invisible player after a kill the player will probably revert back to normal but if you freeze the game with /tick freeze and kill the zombie while the other player is invisible before the zombie gets to it then you will see the player stays invisible and while the environment can interact with it for example you can kill the player with lava if you do /tp @s "otherPlayerName" and place lava at that block but you cannot hit the player.

Screenshots

(after teleporting, flying two blocks up and looking down)

(after placing lava)

Runtime info (please complete the following information):

• OS: Windows 10
• Minecraft version: 1.21
• Mod version: vmp-fabric-mc1.21-0.2.0+beta.7.162

Crash reports / logs
console remains empty

Other mods
tested without any other mods not even fabric api

Checklist

• I am using the official version of the mod.
• I tried the latest development version but the issue persists.
• I searched for similar open issues and could not find an existing bug report on this.

update: reconnecting to the server fixes the bug temporarily

Does it happen without VMP?

nope it was first noticed when I was playing on a server with a couple optimisation mods so I did a binary search and narrowed it down to just VMP

Try reproduce with optimized_entity_tracking_use_staging_area disabled.

btw does this mod provide any performance benefit when theres only one or two players?

it seems to fix the issue at least I wasnt able to reproduce afterwards

btw does this mod provide any performance benefit when theres only one or two players?

It will provide some benefits in most entity-heavy scenarios.