Oh wow, that's a riddle. Not sure how flagpoling is considered. My guess is that it is a new entry. The stamp is not always relevant. For ex, my mother-in-law flew in from Europe 3 days ago, she's got a visitor visa, and her passport was not stamped at all (which also means they allowed her to stay 6 months). They would stamp it only if they restrict her stay to less than 6 months. So, don't base your info on your stamp. If you physically passed the border in one way (exit) and then again in the other (entry), even without entering in another country between those two, I would say it's an entry.