I've not heard of that bit either and it is a very risky strategy going to Thailand with only a month or 2 on your passport. I had seven months left on mine and have renewed it to Jan 2025.
I think all S.E. Asian countries are pretty well the same and my brother's Thai wife was stopped from leaving BKK for a long weekend in Hanoi, Vietnam, because she only had 4 months left on her passport and she needed no advance visa. (that happened AFTER I had checked in and my bags sent on their way but that's another story.....)