The private key displayed for old addresses in the Imported Addresses list is a private key for a compressed public key, even if the addresses is for an uncompressed public key. The uncompressed form of the private key should be the one that is shown.
As you can see in the screenshot, a compressed private key is given. However actually importing that private key into other wallets will yield a different address. Putting it in bitaddress.org reveals the problem; the address displayed (and used) is for the uncompressed public key, but the private key given is a for a compressed private key.
mmikeww
commented
7 years ago
The private key displayed for old addresses in the Imported Addresses list is a private key for a compressed public key, even if the addresses is for an uncompressed public key. The uncompressed form of the private key should be the one that is shown.
Here is a screenshot illustrating the problem: https://i.imgur.com/GVXUPkf.png
As you can see in the screenshot, a compressed private key is given. However actually importing that private key into other wallets will yield a different address. Putting it in bitaddress.org reveals the problem; the address displayed (and used) is for the uncompressed public key, but the private key given is a for a compressed private key.