Non-Im B Multi Entry Visa - only got 30 day stamp?

[STUDMEYER]

Hey All,

Wife, Son, myself are from North America.

This year the wife and I got multi entry Non immigrant B visas. We entered in May for the first time and were stamped for 90 days. Our infant son got a non imm O visa and was also stamped for 90 days. All good as it should be.

We just returned from a week long trip to Singapore. Wife and son flew direct to Chiang Mai, I flew in later the same day via Bangkok.

I received another 90 days stamp in Bangkok but the wife and son only received 30 day stamps. The stamp says "Non-B" just like mine, but the exit date is 30 days instead of 90.

Wife also said the guy at passport control took almost 10 minutes to stamp her passport, meanwhile everyone else passed right through at the other desks. No words were exchanged, no explanation given for 30 day stamp.

She was the first and last traveller at his desk, not possible to see if he treated her differently than other travellers. Maybe it was his first day?

So we have a couple of questions:

1. Is this a mistake? Did the guy at immigration just use the wrong date stamp?

2. Has this happened to anyone else?

3. Is there a way to check if my wife has been flagged or singled out for some reason?

4. What happens now if she over stays?

5. If this is a mistake how do we fix it?

Thanks

SM

Appendix:

Before May, wife had not been to Thailand since October 2014. She had entered multiple times on a 30 day visa exemption stamp in 2014. On her last entry in October 2014 she was hassled at DMK immigration and told to get a proper visa (ie no more exemption stamps)

[nowretired]

Go to the Chiang Mai immigration office and ask for the errors to be corrected.