Four notifications for the latest 1Password beta, but only one for the last beta of another app that I got this morning.
The four came mostly two minutes apart yesterday, 17:20, 17:22, 17:24, and a delay with the last at 17:46, all PDT.
Same here. TestFlight seemed to work great for months, but lately it's been behaving strangely. 1Password disappeared completely for me yesterday. Hopefully Apple will have a solution.