Odds of this getting fixed are probably slim to none. Pet slots,to fix an exploit, are now determined when they are tamed. Nothing can modify this anymore, Pets slots are determined by intensity value. Dreads and banes have an intensity value of a four slot pet, but because were tamed long ago, they were legacied and allow to keep their three slot value. However there was a couple ways they were increased to four slot.. training before patch 98 or releasing and retaming before patch 99. Animal training code says they should be four slot, and since its been already bumped to 4, there isn't much of a way for bleak to fix it without rewriting the whole animal intensity code.