I really don't know. I'd only be guessing. But... maybe if you have some submissions denied/pulled, then they wait longer to submit your stuff, or review it a bit more carefully?
I know I've had some stuff not featured, and it did seem like after that my submissions took longer to get into the stream. But on the other hand it could have just been my perception. I really don't know to what extent the mods actually look at the submissions themselves, and to what extend it's done automatically. Sorry I don't know more.
Hope your submissions go back to normal, soon.