Big thing people forget... there is an individual pity timer for every expansion set. So if you are counting classic packs from quests and brawls these are on another timer than Saviors of Uldum.
Also search for ‘new’ in your collection. I’ve missed legends before when I’m opening packs. Gotten distracted and find it in my collection like a month later.
Have not seen any evidence that the pity timer has broken and every time I see that claim it’s normally individuals who aren’t using any exact tracking data. Breaking the code used on this would generally involve a big patch that effects the infrastructure of the game. Don’t think we’ve had one recently.