In a lot of variations ...
The pathfinding is not the issue ...
since I changed to pathfinding, I have, next to the ai dev, at least 10 extra objects doing constant pathfinding towards me, and it works without a hitch. these objects work without line of sight.
next to this, max 5 objects, doing pathfinding, while moving with a cone of 45, and stand still a cone of 360, distance 800.
Made some progress today:
I added a boolean check prior the los check, so its not using the los behaviour constantly, that made a small difference, then I changed the actions to a function, and it was even beter.
Still not as it should, though.