What brand pressure cooker do you use? Most suggest you sear or brown meat first before adding liquid and therefore do not recommend frying under pressure. However, there was one from Italy that was high priced but could handle frying without liquid. Unfortunately I learned that AFTER purchasing one that did not recommend frying.
I use a presto pressure cooker, very soldily built.
Mine is stainless steel, I dont know if its recommended for frying but I have never had any problems with it, my old one had popped its top once and cause quite a mess.