I have been using 3x3mm QFN from TI on CL12 feeder, they work flawlessly. I think they are not very "light" to be popping out of tapes unlike LED.
The gap you shown is about less than 2mm wide, so unless the cover is really lose and have too much of height left between the base and him, they might jump out.
You seems to be having a lot of issues with feeders I believe? Maybe you can ask Kayo on how to adjust the feeder mechanically, they probably come across this sort of stuff all the time.
I also notice if you buy feeder from different seller, they have slight variation and some perform better and more consistently than others.