Players with a full inventory don't seem to be able to pickup money.
When I picked up the money, I received a golden_nugget in my inventory.

I need more details...

1. Do you use the BagOfGold plugin?

2. Please paste the "DropMoneyOnGroud" section from your config.yml, so I can check your settings, and be able to reproduce your setup.
   I need at least to see:
   drop-money-on-ground-itemtype: SKULL
   drop-money-use-item-as-currency: true

1. No I don't use the BagOfGold plugin.

2. https://pastebin.com/3SLnifpf

I'm running on 1.12.2, latest spigot version (just freshly compiled) and updated to MobHunting 5.2.4.
Using the latest protocollib aswell.

Seems to happen after I updated btw.

I disabled money drop on ground and it's solved. (money goes directly into their balance though)

https://youtu.be/eAHMroccjkw

When you try to pick up money, it raise up the value with strangely , and don't pick up it!
But it don't have issue on 5.2.4

Oh no... its so hard to test all combinations :-(

I will have to look at this to morrow. Im going to bed now.

Ahhh. I see you are in Creative mode... I will have checked mostly in survival mode.... now I know what to look for.

Do you use the BagOfGold plugin?

I don't have BagofGold plugin.
https://youtu.be/eAHMroccjkw?t=1m10s
You don't need to check survival mode, I also record it. OAO

I forgot to record survival mode first, good night.

Thats now solving the problem. Its a temporary. I will release V5.2.5 now and this should fix the reported problem.

Its very hard for me to test all combinations. But I hope I got it right now.

I think this is fixed in V5.2.8

Let me know if I can close this ticket now.