WowAce

Whenever I have Bartender4 on ever since the new patch, switching druid forms with ONLY this addon causes a FPS freeze for a few seconds.

There are other scenarios causing it as well. But since 10.0.5 bartender causes massive freezes randomly during different events... always in combat.   

I can tell this by disabling other addons & tracking addon cpu usage, which goes absolutely bonkers for bartender everytime this happens. 

This is happening for my Rogue as well - happens when I gain or break stealth.  Happens on my other characters, but less noticeable than rogue, where it's a full stop for 1-2 sec

Looks like there was a similar bug about a year ago where Bartender attempts to update every button instead of just the appropriate ones, like stealth bar

Happen for my Rogue and Hunter with Bagnon and Bartender4, this fps lag spike makes me want to stop for few days ; waiting for fix

Even as Warrior with not many stance changes, I'm getting reliable stuttering from Bartender. I've been stuttering throughout raid tonight and disabled my addons one by one hoping it wasn't Bartender, because of all the keybinds I have that rely on it. But in the end when everything else was disabled, the only thing that fixed the hitches was finally disabling Bartender.

If I were running with LUA errors enabled, I would think it would corroborate this, but since Dragonflight,I haven't actually been able to turn on LUA errors because Bartender would apparently just shred the Blizzard frames.

any news on this? its making the game completely unplayable.

I rolled back to Bartender 4-4.14.6 and the enormous lag spikes disappeared. 

I also rolled back to 4-4.14.6 and the terrible stutters went away.