Failing to load key from attachment: "checkint does not match in private key"

[DevSolar]

Environment:

KeePass 2.57.1
KeeAgent 0.13.8
OpenSSH 9.9p1 (Cygwin)

Steps to reproduce:

• Create new database Database.kdbx (Master Password is "KeePass")
• Create new key "SSH" in database
• Create new SSH key in Cygwin terminal (ssh-keygen -C foo@example.com -f ~/.ssh/id_foo) using the password from the KeePass entry as pass phrase
• Edit the database key, adding ~/.ssh/id_foo as attachment
• Set KeeAgent options: Allow to use this entry, Manage Key Files / From Attachment / id_foo)

Note: The comment ("foo@example.com") doesn't appear in the Key Info section. I've seen there is at least one other issue mentioning this, and it's not the problem I am having -- but perhaps there's some underlying common key parsing issue here.

• Close Edit Key dialog
• Select Tools / KeeAgent dialog
• Add Key / From KeePass
• Select the SSH key just added to the database

Expected: Key gets loaded by KeeAgent.

Observed: Error dialog reading:

KeeAgent: Error while loading key from entry "Database\SSH"
Could not load file from attachment "id_foo"
checkint does not match in private key.

Possible causes:

• Passphrase was entered incorrectly
• File is corrupt or has been tampered

Checks:

Saving the attachment from KeePass yields an identical file to the one in ~/.ssh/id_foo. Verifying the key with "ssh_keygen -y" (and the password from KeePass) works as expected.

I added the database (including the SSH key) as attachment.

Database.zip