Comment # 14 on bug 1091818 from Neil Rickert

It does appear to be fixed, but not as you describe.

On a fresh login into Plasma-Wayland, gpg-agent is not started.
On a fresh login to Plasma-X11, gpg-agent is started.

A fresh login to Plasma-Wayland, so gpg-agent is not running.
I use a command that requires gpg-agent.  And that starts gpg-agent.
I then logout.
I next login to Plasma-X11.

I see that gpg-agent is still running from my previous Wayland session.
The command that started the X11 session did not attempt to start gpg-agent
this time.

It looks as if the startup script for Plasma-X11 is now checking whether
gpg-agent is already running, and only attempting to start it if not already
running.  And that solves the problem reported for this bug.