What should I do about TM30 updates after traveling within Thailand and returning to Chiang Mai?

Hi all. I have yet another TM30 question (probably only applicable to Chiang Mai province residents).

My wife and I recently returned from an overseas trip. We both have a status of valid non-O extensions based on retirement. The day after we re-entered Thailand, we went to the second floor Promenada immigration office and they updated our TM30 by logging in our latest arrival date on the computer and putting a small date stamp on the form. This was easy and took only a few minutes of waiting with no paperwork or forms needed which coincided with what other people told us on this forum.

We're now planning on taking a trip that involves driving to Bangkok, leaving the car in a long term lot and flying to Vietnam. Upon returning to Bangkok by air, we'll then be traveling further south by car for about four to five weeks before returning to Chiang Mai.

Since the TM30 updates only seem to matter in CM, are we expected to then go to Promenada five weeks after arriving back in Thailand to update the TM30 and try explaining that the reason we couldn't come within 24 hours after arrival (or even 7 days) was due to our onward travels within Thailand?

Will they fine or scold us for being late? And if we don't bother updating the TM30 is there a chance that the next time we do a 90 day report online it will be denied due to a conflict between the latest arrival date on file and the now outdated TM30 date stamp? My understanding is you can only update the TM30 in the province it's valid for so it sounds like going to a Bangkok immigration office after returning isn't an option and they wouldn't care anyway because only CM makes you do this redundant and tedious task every time you leave Thailand.

I should mention we've successfully done our last two 90 day reports online and I know you need to fill in your last arrival date as well as the current visa number (we used the visa number on our re-entry permit when we filled out our new arrival card since I'd asked that question previously and that worked just fine).

I know the question sounds kind of redundant and unnecessary but I'd rather go waste a day in Bangkok if need be than pay unnecessary fines or argue with immigration folks. And the obvious answer of flying from CM instead of BKK is not an option we prefer so please avoid that answer. Thanks to all.