I always thought the pair left WWF due to dissatisfaction over pay.
I'm not sure about the drug test issue, although it wouldn't surprise me - at least concerning Tully.
Regardless...
Bobby ran into Blanchard at a Cauliflower Alley banquet (or something) several years back.
He happily approached Tully and asked how his Dad Joe was doing.
Tully fired back, “Why don’t you ask him yourself?”
Bobby asked him what the heck was the matter.
Tully said, “You badmouthed the Brain Busters on WWF TV after we left.”
Bobby tried to explain how the fed had to give a reason for Arn’s & his departure.
Vince (or Pat) told Bobby to mention in his following week’s promo that the Brain Busters were too hard to do business with & he had to let them go.
That was it.
And Tully was pissed over that – a work – as if it had somehow buried his character & storied career.
I doubt that most fans so much as gave it a second thought, and other promoters & bookers would have known it was a work.