If this bug is real it can make people lose a lot of bitcoin. People make paper wallets and send moeny to them and never check if the key matches the address or not. How do one check the key offline?
Download Electrum on a machine that has never had it installed before & unplug machine from internet.
Run Electrum and then Wallet --> Private keys --> Import [type in the private key and make sure it brings up the correct address.]
Then delete all the info from the proper locations on your PC to be sure that there is no record of the private key.
-Dave