This is correct and I have seen a recent story about a person with dual citizenship entering Thailand on foreign passport and overstaying for 3 years as they thought it would be fine as they have Thai citizenship. When they went on vacation, as they exited Thailand, immigration told them they were not allowed to come back for years (not sure how long).
BTW my son's are 15 and 17 and they are not in overstay.
Not in overstay and we will just have to extend again until they can exit the country and reenter as Thais. It just gets annoying to have to do 90 day reports and visa extensions when they are citizens.
Should I have received a 'receipt of notification' when coming back from my home country on my reentry permit? I didn't receive one and I am a little nervous about not having the paper in my passport. All I have is the reentry stamp dated July 14th, 2019.