Can't pickup ammo when no clip is in gun

If I interrupt my reload sequence by switching weapons, and am left with a gun with no clip loaded, I cannot pick up ammo from a supply box. A single tap of the USE button does nothing. If I finish the reload sequence, then I am able to pickup ammo.

Bear in mind that you can't top off your loadout of magazines, so if you regularly reload a magazine at the start of the round you won't be able to pick up more up until you expend one mag fully or toss it away using speed reload.

Is this the case for you ?

The issue happens when I have no magazine in my gun. When that happens, I am unable to pick up any new magazines from the supply boxes.

This is what it looks like:

When I am in this state, I am unable to replace any of my spent magazines. Single-tapping the use button on a supply box does nothing. If I finish the reload sequence, I am then able to replace my spent magazines.

To clarify this is what is supposed to happen:

This is what looks like if I've used a little of each of my magazines, and still have a magazine in my gun:

If I single-tap the supply box, it replaces my partly used magazines, except for the one in my gun. This is the expected behaviour:

It should do the same thing if I don't have a magazine in my gun.

If I single-tap the supply box, it replaces my partly used magazines, except for the one in my gun. This is the expected behaviour:

If you single-tap it grants you one full magazine, mags are sorted by how full these are, near empty ones are put at the end of the queue.

However i was able to reproduce your initial issue, so thank you for your report !