When buying cards for your caravan deck, they will just sit in your inventory and you won't be able to add them to your deck. This is fixed by putting the cards into any container, then retrieving them. The cards then go straight into your deck. (Note: There is a workaround for this bug. If you place the cards in a container and then remove them from the container one at a time, they are then added to your caravan deck. Similarly, placing them in a companion's inventory and removing them also adds the cards to your deck.) - vault wiki

supposedly this is only a PC issue but this happened to me when i made a new save with the patch applied. it's pretty annoying

This is also an issue on the xbox. V annoying goonna go try this now

Yes the trick, putting all cards to a follower then taking them back works wonderful

I'm having this issue also, on Xbox 360, but I can't give them to a follower or put them in a container because they don't show up in my item list at that time. I tried dropping them from the PipBoy items screen and then picking them up, but that didn't work. Please fix this ASAP!

This is also the same for ammo parts (shells, powder, lead and so on)
Same thing fixes this.

And are you search in misc as i think you have to just do it in items

Yeah, my wife realized this on her character so now I'm good to go.

BTW... in addition to everything else mentioned previously, this also applies to bulk ammo boxes (which you should only use as a last resort).