Uncaught error when mint second nft

[petia-latinova]

To reproduce that issue please go through the steps:

1. Fund RandomSVG contract with just 0.2LINK in total
2. Press “ Request NFT”, wait for the transaction to finish and continue with the second part and press the button “Finishing Minting”.
3. Continue and press "Request New NFT". There is the following error just in the console:

4. Press again "Finish Minting"

5. Press again "Request New NFT" and you have the following unhandled exception: