I've given up on having separate @Action and @Read/Review folders for email. Why? Well, the reading is just another kind of action - it's something that I'm required to do with the email before I bin it or file it.
I suspect that one problem might be that you're using the folders themselves as your context lists. This is a bad idea for a few reasons. Firstly, it means you've got two more places to look when you're looking for something to do. Have as few buckets as you can get away with, and I suggest you can get away with just one @Action bucket.
Secondly, an email is a poor Next Action trigger/marker. The title usually doesn't tell you what to do with the email, so you have to re-read and re-decide each time you go into the folder. That's wasting time and energy.
Thirdly, if you're using those two folders as context lists, you're scattering your lists all about the place, which means you're not making the best decisions on what to do in the moment. Just because a project or Next Action arrives as an email, doesn't mean that email is the best/only way to deal with it. In fact, a lot of the time you're going to be doing something else anyway.
So you've got two email folders, which contain a fair variety of tasks/NAs, plus whatever context lists you're keeping either on paper or electronically. That's almost a guarantee that something will drop off the radar sooner or later.
I'd extract the NAs from the emails and put them on the lists, and just keep all the actionable emails in one holding pen so you can find them when you decide to do the actions they cue. Make your decisions based on the actions required, not on how they appeared on your radar screen.
One other tip: in the past, I've gone through phases where I've dated every NA when I write it on the list. That way, I can see when things are getting a bit stale. As The David says, it's a tiny bit of effort that pays off hugely the few times you need it.