Claiming funds in the Ethereum network requires ETH in the destination address to pay fees since the claim is a call to the contract holding the funds. A call is a TX, and a TX needs to pay fees to the network. In all the other networks this is not necessary since Liquality pays for that fee.
In the other hand, Refunds in all networks, but Bitcoin, need the source address to have funds to execute the refund call.
- Swap from MATIC to ETH: requires ETH to Claim, if successful, and requires MATIC if unsuccessful to pay for the Refund call fee
- Swap from ETH to ANY OTHER COIN: requires no fees to Claim, but requires ETH if unsuccessful to pay for the Refund call fee