I can confirm that Chiang Mai Immigration are still using the old rules, for inter-province travel !
My online 90-day-Report was declined ten-days-ago, because I had stayed at a Chonburi resort in November, and their report of my (temporary) hotel-stay had overwritten my permanent residential-address, which has been on my most-recent TM30 (back in 2019).
There was a 3-4 hour queue at CM-Immigration, when I went in and tried to correct their records, so I gave up ! And will try to re-do it next September, just before my next visa-extension is due. No point doing it before then, as I have several overseas-trips planned, and also some inter-provincial travel, before then !
A temporary trip to another province logically ought not to over-ride one's permanent-address, as notified on 90-day-reports and used on all Immigration paperwork for the past 19-years, but it does in Chiang Mai ... one can only live with it, until it changes again ! ????