A few days ago I had a client who mentioned seeing something unusual in their Gmail testing. Their messages, which usually end up in the Promotions tab, had been hitting the Primary tab for almost two weeks. They reported clients had seen the same behavior. It’s not unheard of for this to happen at Gmail, but typically it lasts no more than a couple of days.
Turns out, lots of people have been asking the same question to the team at 250ok. Matt Vernhout confirmed via blog post yesterday that the deliverability tools provider is seeing this behavior as well.
There is no official acknowledgement from Google, although yesterday @Gmail replied to a Twitter user’s complaint with instructions on moving mail between tabs: