Join Error when webinar is in Preview Mode

Description
We have regular/recurring webinars. The host starts the webinar in preview mode while preparing the presenter. When the user is in the waiting room, and the webinar is in preview mode, zoom attempts to join the meeting. It fails to join, with a popup message:
Joining Webinar Timeout or Browser restriction

Meeting has not started

Error Code:3008

This is new behaviour since upgrading from 2.16 to 3.8.5. Still exists in 3.8.10

Browser Console Error

join error code: 3008 Meeting has not started zoomus-websdk-main-client.umd.min.js:84:1185245

handleRendererTypeInProps() final rendererType=1 gpuBlacklist=null js_media.min.js:1:557313

websocket onclose event: type:close code:1006 reason: timeStamp:39518 target:3 url:wss://zoomct1342241527rwg.cloud.zoom.us/wc/api/89102555090?ts=1727139361080&auth=iVChMab2I49MtiztW-71HR-V4LOBZDdRJ2e7gzVhKPA&trackAuth=7FdTn6ufKoYhrB8Gb5FOlEqLxCEK7hJwxWJg7epkLig&mid=WjqlkkeGTQya5PD6RZg7HA%3D%3D&tid=v%3D2.0%3Bclid%3Dus02%3Brid%3DWEB_71dfe8bc9fa837ddf5219da5bc393c58&browser=Firefox130&ZM-CID=713604a2-cf3b-4b24-9f6b-13ca4977179b&lang=en&wccv=20.6.0&jscv=3.8.10&isCamera=1&as_type=2&rwcAuth=MTcyNzEzOTM2MTQzNC5qWclOXI-woWm31IG82dVemjQUaJD92Y-HELGrl-RY3A&islch=1&email=brian_mould%40hotmail.com&cfs=0&clientCaps=266849914&clientOS=win&audioFeature=12 @zoom_meetingsdk.js:10018:24

close web socket connection… @zoom_meetingsdk.js:10020:24

Uncaught (in promise) TypeError: URL constructor: undefined is not a valid URL.

initAudioDecode https://source.zoom.us/3.8.10/lib/av/js_media.min.js:1

WebRTC: ICE failed, add a STUN server and see about:webrtc for more details
WebRTC: ICE failed, add a STUN server and see about:webrtc for more details

Which Web Meeting SDK version?
3.8.10

Meeting SDK Code Snippets
The code snippets that are causing the error / issue so we can reproduce.

To Reproduce(If applicable)
Steps to reproduce the behavior:

  1. Create recurring webinar. Enable ‘Preview’
  2. Join webinar as user
  3. Start webinar in Preview Mode
  4. See error within 1 minute

Screenshots
image

Troubleshooting Routes
The troubleshooting attempt types you’ve already exhausted, including testing with the appropriate sample app (found on Zoom · GitHub).

Device (please complete the following information):

  • Across all browsers/devices tested.

Additional context
Web SDK running in Client View, in a Vue3 web application.

Is there any chance of assistance here? Anyone else encounter this issue?
Thanks.