I started to have the same issue 2 days ago. Never experienced game stuttering in combat with displaying all combat messages before, is this bug reappears after some kind of patch or it is never fixed?
I am also dealing with the in game stuttering as well. Im not sure if it is my combat log, but I did try to look at some older threads to help me out with this issue. The in-game stuttering happens for me when I engage a pilot. I am currently uninstalling and re-installing game lol.
Also ran into this issue. Found that same thread indicating it was a logging issue.
Recommended workaround was to either disable combat messages in game or to prevent write access to the log directory via OS settings. In my case I did the latter and am no longer seeing stutters. Directory in question on Windows is in Documents/Eve/logs/Gamelogs.
Can’t say whether or not the bug ever got fixed but for my local setup it is new this year so wouldn’t have seen the issue back in '18 when it was listed in the thread