Legendary Dragon sales notifications

I keep getting the notification “A legendary dragon is on sale now!” Every few days, but every time I click into it I can’t find any legendary on sale. I’m missing 3 still: Shellfire, Submaripper, & Elder Sentinel; so I’d think it would still be possible for the sales to appear. I check the offer tab, the tabs for the legendaries themselves, and the shop, but it always seems like I’ve hallucinated the notification.

Is there some obvious place for these sales that I’m missing? Or some way to turn off only those notifications?

I’ve gotten Fault Ripper and I think another one via sales in the past, so it’s unlikely that I’m just dumb and missing it; albeit possible nonetheless.