From the blogto article linked by op:

He says that "After a couple of sips, it became soggy and started to stain. Thereafter, I could taste a few small lid pieces in the drink, which was like 'yuck.'"

Yep sounds like terrible design and Tim's cheapen out in the material. I've had non plastic caps that were much better than that.

You know what would bring us back to the good old days? A real ceramic mug you can use to sit down, drink it slowly and enjoy. But I haven't been to a Tim's in a while where the server would ask if I wanted a mug or to go. Maybe the lady would call that woke too?