This is a first that I'm aware of. Did you already reach out to Customer Support?
This thread was added on August 30, 2021, with posts from Sunshine.
7 hours ago, Encjon said:i found a solution for this, you need lower than 70/94 ( in my case round about 60% ) item slot space, than you can get the lcoins
Confirming that any issue in collecting from the Dimensional Merchant is present due to weight and not having enough inventory space to claim the item. You can still collect but you'll have to store some stuff in your warehouse first.