Refresh token ignored

Hi, I'm using GNUS with nnimap and this plugin to authenticate against mail.google.com.

When enabling this plugin, the minibuffer want that I paste the code google gave me after allowing my app. this works as expected.

But, when I close emacs or even after some time, I will be redirected to google again to allow the app (GNUS) to connect and the minibuffer wants the code again.

I verified the existence of the plstore file and the gpg encrypted content of the token. Everything seems to be correct, but I thought I don't have to allow again and again GNUS to connect to gmail.

for me it seems the refresh-token is not used. What could be the reason for that behaviour? any idea how to debug to find the misconfiguration on my side?

thanks marko