Error when restart computer(Gnome version 3.38.6)

[Ga0aG]

I can use kitchenTimer after installed, but when I restart computer, error happens.
Last time use I might delete the default timer and create some new timers.

Journalctl log

4月 17 14:00:45 PF4D9XTB gnome-shell[36988]: INFO: [kt timers] Attaching indicator
4月 17 14:00:45 PF4D9XTB gnome-shell[36988]: INFO: [kt timer: 5 minutes] Create timer [5 minutes] duration=[300]
4月 17 14:00:45 PF4D9XTB gnome-shell[36988]: INFO: [kt timers] Adding timer [5 minutes] of duration 300 seconds [7daa22cf-d089-46b4-8321-3d6a9d211f10], quick=false
4月 17 14:00:45 PF4D9XTB gnome-shell[36988]: JS ERROR: Extension kitchentimer@blackjackshellac.ca: TypeError: timer is undefined
                                              restoreRunningTimers/<@/home/mujin/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/timers.js:257:7
                                              restoreRunningTimers@/home/mujin/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/timers.js:255:13
                                              attach@/home/mujin/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/timers.js:82:20
                                              _init@/home/mujin/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/indicator.js:43:29
                                              enable@/home/mujin/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/extension.js:50:27
                                              _callExtensionEnable@resource:///org/gnome/shell/ui/extensionSystem.js:167:32
                                              loadExtension@resource:///org/gnome/shell/ui/extensionSystem.js:350:26
                                              _loadExtensions/<@resource:///org/gnome/shell/ui/extensionSystem.js:588:18
                                              collectFromDatadirs@resource:///org/gnome/shell/misc/fileUtils.js:27:28
                                              _loadExtensions@resource:///org/gnome/shell/ui/extensionSystem.js:567:19
                                              _enableAllExtensions@resource:///org/gnome/shell/ui/extensionSystem.js:597:18
                                              _sessionUpdated@resource:///org/gnome/shell/ui/extensionSystem.js:628:18
                                              init@resource:///org/gnome/shell/ui/extensionSystem.js:56:14
                                              _initializeUI@resource:///org/gnome/shell/ui/main.js:269:22
                                              start@resource:///org/gnome/shell/ui/main.js:159:5
                                              @<main>:1:47`

[Ga0aG]

After I comment timersInstance.restoreRunningTimers(); in /home/<user_name>/.local/share/gnome-shell/extensions/kitchentimer@blackjackshellac.ca/timers.js, in can start properly