Could it be that your strength gains precluded your size gains? In other words, you got stronger for a while but didn't get much bigger, and then viola your size gains caught up with your strength gains. But, if there was a good amount of time btw the 2, say at least 6 months or so, then yeah I am confused. When I say stronger, I mean with the same exercise with the same form for a certain TUL, not some 1 rep max.