Steps to reproduce the issue:

1. Running the 5.0.1 on mainnet with wallet locked.
2. Set the custom fee to 0.0001 PIV/kb (not sure if that plays the role too, but issue can be reproduced with it for sure).
3. On a single transparent address there are multiple UTXOs, all of them Cold Staked (delegated to the same cold staking address, make sure there are at least 10-15 UTXOs).
4. Open Coin Control, select all UTXOs from the address, copy-paste the After Fee amount into the Amount field and try to send them to the outside PIVX address.
5. The following error with appear: