Launching via Plasma shortcut removes ssh-agent's environment variables

Running Plasma 5.27.10 on Debian testing/trixie. An ssh-agent is launched via user service /usr/lib/systemd/user/ssh-agent.service and its socket is exposed in my session's environment variables. All good so far. OK situation: when I start a terminal program (e.g. XTerm, zutty, Konsole) via the Application Launcher ("Plasma Start Menu") the ssh-agent variables are exposed in the bash environment as expected:

$ export | egrep SSH
declare -x SSH_AGENT_LAUNCHER="openssh"
declare -x SSH_AUTH_SOCK="/run/user/1000/openssh_agent"

Not OK situation: if, however, I start the _same_ terminal program using a shortcut key (configured in System Settings -> Shortcuts) the bash environment has changed. A few environment variables have disappeared but what most concerns me is the loss of ssh-agent socket export:

$ export | egrep SSH

Obviously all SSH connections in this terminal instance start asking me for the password to my private key file, which is counter-productive. Why is Plasma removing ssh-agent's environment variables when launching an app via shortcut? More importantly, how do I stop it from doing that? ------ _Extra details, possibly not relevant._ List of variables that are _removed_ from shortcut-launched environment (compared to Application Launcher):

FONTCONFIG_PATH="/etc/fonts"
GTK2_RC_FILES="/etc/gtk-2.0/gtkrc:/home/user/.gtkrc-2.0:/home/user/.config/gtkrc-2.0"
GTK_RC_FILES="/etc/gtk/gtkrc:/home/user/.gtkrc:/home/user/.config/gtkrc"
SESSION_MANAGER="local/nut:@/tmp/.ICE-unix/1583,unix/nut:/tmp/.ICE-unix/1583"
SSH_AGENT_LAUNCHER="openssh"
SSH_AUTH_SOCK="/run/user/1000/openssh_agent"

List of variables _added_ in a shortcut launched environment (compared to Application Launcher):

KGLOBALACCELD_PLATFORM="org.kde.kwin"
QSG_RENDER_LOOP="basic"