I have also this pb. It seems gpg cannot handle more than /etc/apt/trusted.gpg (one keyring) + 39 keyrings in /etc/apt/trusted.gpg.d/ : https://lists.gnupg.org/pipermail/gnupg-users/2013-December/048571.html
I have also this pb. It seems gpg cannot handle more than /etc/apt/ trusted. gpg (one keyring) + 39 keyrings in /etc/apt/ trusted. gpg.d/ : https:/ /lists. gnupg.org/ pipermail/ gnupg-users/ 2013-December/ 048571. html