Background:

1. I relocated from the UK to Thailand in 2005 on a Non-B (one-year) visa.

2. When this was due to expire, I transferred it to a "Retirement Extension" when is required to be renewed annually, the renewal date falling in September (2006).

3. My previous UK passport was due to expire in July 2010, so I renewed it at the British embassy in Bangkok; I believe it was sent to Hong Kong for renewal.

4. Note: the renewal date of the new passport was not 10 years from the date of issue, but instead was April 2021 (an additional 9 months), but I thought nothing of it.

5. In January 2021 I started the process of renewing my passport, which took approx. 6 weeks.

6. My next 90 day was in March 2021. I requested to have my annual visa transferred to my new passport (and I thought that it was). 

7. My next 90 day was in in the June and this once again went through without incident.

8. I went in for my next 90 day renewal - which I always time to coincide with my annual visa renewal - in the the September (2021). This is when the shock happened.

9. The officer at the 90-day point looked at my passport and swiftly turned me away, stating that my (annual visa) had expired 90 days after renewing my passport.

Note: it was totally my fault for not checking that my annual visa had been transferred, so why did they give me another 90-day renewal in the June???

10. I will not go into the details of how I sorted this problem out, but I would like to draw attention to the Foxtrot Uniform of the UK passport office giving me an exptra 9 months on my 10 year passport. For another example of how this affected a UK passport holder, click on this: https://www.msn.com/en-gb/travel/news/brexit-dad-50-has-to-pay-3k-and-drive-over-1-100-miles-after-being-caught-out-by-new-passport-rule/ar-AA1fEsqy?ocid=hpmsn&cvid=5482b344a0ce4de69aad76e4d32eb49b&ei=20

52 minutes ago, safarimike11 said:

4. Note: the renewal date of the new passport was not 10 years from the date of issue, but instead was April 2021 (an additional 9 months), but I thought nothing of it.

That was the regular procedure prior to October 2018 as the period still valid (up to 9 months) on the old passport was added to the new one.  Since October 2018 passports are issued for 10 years without any extras.

The issue was that, although the current permission to stay was transferred correctly, just transferring it to a passport with a later expiry date does not automatically extend the permission to stay. Always make sure you understand the stamps in your passport.