I think this issue is solved. For systemd, I need to run this as --supervised option not the --daemon option. The --daemon option has bug.

OK I found a very interesting thing here, @werner and finally I can reproduce this problem:

Actually I don't use systemd unit to start gpg-agent (creating that service file in systemd and make it start automatically) but I run it manually within the script. Also the script has selfcheck not to run multiple gpg-agent like below:

Update found out the answer for this mystery but I need to know why from you guys:

Update: Using --use-standard-socket argument to run this does not work and gpg-agent still create new process. New findings:

Just to acknowledge here: I notice that the new gpg-agent random process respawn with an obsolete argument using --use-standard-socket. I will run my gpg daemon using this absolete argument to see if it can block this random process. [updated the script]

Thanks for your reply. I can confirm from my observation from the log this is a bug where I'm able to reproduce this every day. I will post this to mailing lists.

I'm now able to kill the respawn process in the script (updated the script). But I need confirmation if this is a known bug ?

I can create a script to manually kill the 2nd process, but can u guys confirm with me that this is a known bug ?

Just to let you know that , using --homedir option also has the same problem I noticed today. I got email each minute like this:

Ok let me update what I did next: