NOTE:
Use RPC to send coins if you get a warning using the send tab in the GUI...
EXAMPLE:
First fully unlock your testnet wallet.
sendtoaddress jMZfW9yKwbcujSpTWQnmUn3aJkhgg2Wix5 before and after the amount of coins>
I'm still unable to send tKORE to that address

Invalid KORE address (code -5)
Note: I'm still using v0.13.0.1
Since you were sent a single large block of coins if they staked then they need to mature.
Try closing wallet and put in conf file:
staking=0
restart and let a bunch of blocks go by for few hours and then restart and try to send.
Use the console to send them...