I restealth (prowl) on my druid vs pet classes all the time…
Occasionally I have had lock / hunter pets follow me after a RE, but they don’t attack.
Its been a bug since the start of classic that has persisted for all this time.
In old retail TBC / Wrath it did not happen like this, either you got the RE or you didn’t, there was never pets following me into prowl so long as there was no hunters mark on me.