FYI Jomtien Immigration.
I have just done a 90 day report. The TM30 office is now manned up with 3 desks and it's packed out. I would say if you've not done a TM30, go and do it before you need to do your extension etc unless you want a delay.
They confirmed they expect a TM30 report within 24 hrs of returning, no matter what visa or extension your on, if you spend time out of the country AND/OR out of Chonburi province.
Don't shoot the messenger.
TLDR : Answer Summary
The Jomtien Immigration office is currently busy with TM30 submissions. It's recommended to complete a TM30 report promptly after returning to avoid delays with visa extensions or 90 day reports. The office confirmed that a TM30 is expected within 24 hours of return, regardless of the visa type, if you have spent time out of Thailand or Chonburi. Note that this information specifically pertains to the Jomtien office.