Yes world partitition is enabled 
Will send you the logs as DM
Also just tested and still happening as of 28.20.
Logs do not seem to have any indicator that could cause the bug. I am still pretty sure the lag / rubberbaning is caused by AI Navmesh creation / adjustment.
As the player is building the AI has to check for a new path , the navmesh changes which causes the stutter / rubberbanding