Transmuted Bramblewitch effect issue

In my last round in battlegrounds I had 2 transmuted bramblewitches and instead of setting the attacked minion’s stats to 3/3 as they should - they only lowered the attack by 3. It didn’t attack a static effect minion - it attacked the undead dragon that its deathrattle is to give its attack to 2 other minions. in previous rounds I played it effected it as it should, but for some reason it didn’t do that today…

That dragon is also an undead, could they have buffed the attack of their undead miions permanently in-between your turns ?

Nope, the effect came in during the combat, what was supposed to happen is that the transmunted brambble witch should have set the stats to 3/3 and then after the dragon is dead - the attack the other minions would have gotten from it should have been 3 at most and that is what happened in the million times before I encountered that but for some reason it didn’t happen now

Buddy, the Dragon was buffed by perma buffs before, and the Bramblewitch only sets base stats and normal buffs to 3/3 , not the perma buffs.
For example, lets say the Dragon was buffed 10 times by perma buffs, from base stats 6/3 it becomes 16/3. Bramblewitch attacks will set it’s stats to 13/3.
Hope this helps.