Phone or desktop - both seem to be delayed. I was checking some timestamps of recent posts against the timestamps of received notifications. Typically there's an hour-and-a-half lag before getting the email of a new post. But then again, since the email I use for this is a Yahoo domain, it may very well be Yahoo.
I've solved the problem by subscribing to a nice RSS app on my phone and I'm getting (all) new posts within ten minutes. Unfortunately, when you do a search for 'RSS Reader' on Google Play, there's about six gazillion of them. And on the app itself, I can't find a developer's name or version number. If I find it, I'll post it.