From what my now poor lock has experienced the pet skill bug is in effect on warlocks aswell. When i moved here I saw that my pets have no skills leveled on them at all so i thought this was just some random bug and went ahead and taught my imp, voidwalker and felhunter the highest possible rank of their spells (ignored succubus since im DS/Ruin and only use it to get the spellbuff). Tonight i was helping a guildie with a quest and happened to die. Once i ressed and summoned my voidwalker again all his skills are gone along with the other pets in my arsenal, If this helps troubleshooting there's not even a petskill tab like there used to be once you've successfully summoned a pet meaning they dont even have rank 1 abilities anymore, my rain of fire spell has the same effect as the blizzard spell not going damage to mobs at all while hellfire works just fine.
If this was just a pet-rename issue then the problem wouldn't have persisted thru summoning and training pets since their names should be unique to the server by then.
Im aware that people are working hard trying to figure this one out but im quickly running out of funds having to retrain pets everytime i actually have to use then (again beeing DS/Ruin helps)