Yes, I wondered that too. However, given how productive the skimmer has been, I am very disinclined to test that theory.I wonder if you still went skimmerless after "cooking" the rock, if the problems would have alleviated.
By the way, just in case some are not familiar with the term "cooking", the live rock is placed in a saltwater bath with heat, light and powerheads and water changes done until whatever nuisance you are trying to eliminate has completely disappeared and there are no detectable nutrients in the water. Most of my coralline algae seems to have survived this process, although not all.