Checked 0.4.15 because you asked. I don't know what is happening. Sure, Freeboy gives CPU load, but it's mild (in green range, very little CPU load). Then I copied the pattern over to 3O to do a baseline check, and it goes to about double of Freeboy's CPU load. But both are in green range. Therefore testing with 0.4 gives invalid results, whatever the case. BUT the bug doesn't seem to be there.
Also checked 1.1.2: Freeboy gives mild CPU load, 3O gives double to triple of that. But both are still in green range.
Therefore, I can assume there is no bug.
Then, of the four versions I have, freeboy plugin does this only in 1.2.0 and 1.3 alpha.