I had the same problem and fixed it thus.
System > Preferences > Encryption and Keyrings > PGP Passphrases
Then set "Remember passphrase for xxx minutes" and this, in my case, resolved the problem.
I had the same problem and fixed it thus.
System > Preferences > Encryption and Keyrings > PGP Passphrases
Then set "Remember passphrase for xxx minutes" and this, in my case, resolved the problem.