Having the same issue.
First of all, sometimes you need to try place the medic/support crate down 2-3 times repeatedly pushing the button because for some reason it doesn't appear (the skill didn't go into cooldown either).
The other issue what op said, crate goes through the ground, barely or not at all visible.
The crates badly need an ingame siluett icon as well so others can easily see it and pick the supplies up! At this moment people barely noticing it, due to visibility issue and also because of the bug.
Kind of game breaking issue, since even the weekly objective were based on crates so it needs to be fixed asap please!
Im on PC.
