I'd say about 10%-15% of my weapon pickups and turbos do not show up in my inventory, even though they disappear when you run them over AND it will read off the name of it.
About 20-30% of my flamesaws and power missiles do not register. I know they hit because you can see the impact/contact on your target with the sparks and also see them get quickly knocked/jolted back.
It's been plaguing me as of late and I go full rage mode when it does. I'd dare say the tweaking they've been doing may have something to do with it. I've noticed a lot of weird stuff every time we're about to get a patch or when they start messing around with the vehicle numbers.