[BUG] Got duplicated ipc service in process

[laowalter]

Checklist before submitting an issue

• I have searched through the existing closed and open issues for eww and made sure this is not a duplicate
• I have specifically verified that this bug is not a common user error
• I am providing as much relevant information as I am able to in this bug report (Minimal config to reproduce the issue for example, if applicable)

Description of the bug

I have two monitors, one is DP-1 the other is DP-2.
When run eww open bar0, it works good, but I found there two duplicate script/ipc running process. I thought there should be one bash script/ipc DP-1.

$ eww open bar0
$ ps aux|grep ipc
user 22137 0.0 0.0 13304 3584 ? S 22:32 0:00 bash script/ipc DP-1
user 22140 0.0 0.0 13304 2316 ? S 22:32 0:00 bash script/ipc DP-1
user 22276 0.0 0.0 12404 2048 pts/0 R+ 22:32 0:00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn ipc

Reproducing the issue

;;Variables (defpoll hm :interval "60s" :initial "initial-value"date +%H:%M) (defpoll sec :interval "1s" :initial "initial-value" date +:%S`)
(deflisten workspace_ipc_DP1 "script/ipc DP-1")
(deflisten workspace_ipc_DP2 "script/ipc DP-2")
(defvar workspace_eventbox "workspace eventbox")

;; Window bar
(defwindow bar0
:monitor 0
:stacking "fg"
:windowtype "normal"
:exclusive true
:orientation "horizontal"
:focusable false
:geometry (geometry :x "0" :y "0" :width "100%" :height "20px" :anchor "top center")
(box
:class "workspace"
:halign "center"
(literal :valign "center"
:content workspace_ipc_DP1)))

(defwindow bar1
:monitor 1
:stacking "fg"
:windowtype "normal"
:exclusive true
:orientation "horizontal"
:focusable false
:geometry (geometry :x "0" :y "0" :width "100%" :height "20px" :anchor "top center")
(box
:class "workspace"
:halign "center"
(literal :valign "center"
:content workspace_ipc_DP2)))
`

I run once eww open bar0, but got the two duplicated sessions
$ ps aux|grep ipc
user 22137 0.0 0.0 13304 3584 ? S 22:32 0:00 bash script/ipc DP-1
user 22140 0.0 0.0 13304 2316 ? S 22:32 0:00 bash script/ipc DP-1

Expected behaviour

Should be one process

user 22140 0.0 0.0 13304 2316 ? S 22:32 0:00 bash script/ipc DP-1

Additional context

No response