Calendar grid does not render on Firefox

[st3iny]

Steps to reproduce

1. Open the calendar app.
2. Wait for it to load.
3. Observe that the grid is not rendered at all.

Expected behavior

The grid should be rendered.

Actual behaviour

The grid is not rendered. Only the left bar is rendered.

Calendar app version

main, stable4.2, v4.2.4

CalDAV-clients used

No response

Browser

Firefox Developer Edition 111.0b4 (64-Bit)

Client operating system

Linux x86_64

Browser log

Two errors are printed multiple times:

1. Error in callback for watcher "options.headerToolbar": "TypeError: can't access property "pauseRendering", calendar is undefined"
2. TypeError: can't access property "pauseRendering", calendar is undefined

They both occur in FullCalendar code.

Context of 1.

[Vue warn]: Error in callback for watcher "options.headerToolbar": "TypeError: can't access property "pauseRendering", calendar is undefined"

found in

---> <FullCalendar>
       <CalendarGrid> at src/components/CalendarGrid.vue
         <NcAppContent>
           <NcContent>
             <Calendar> at src/views/Calendar.vue
               <App> at src/App.vue
                 <Root>

Context of 2.

TypeError: can't access property "pauseRendering", calendar is undefined
    handler FullCalendar.js:112
    VueJS 11
    addCalendar calendars.js:76
    wrappedMutationHandler vuex.esm.js:844

Additional info

It works fine with Chromium.

[st3iny]

It does work with Firefox Beta though. This seems to be an issue with Firefox Developer Edition specifically.