That's good to know. I did wonder about foam after.
I had the mdf strip on the right already so used double sided tape the caulk on the back.... Which was very tricky to apply in some spots. Then the left was partially self leveled and higher so I just used more caulk.
Foam is a really good way of getting an edge to a pour as well. We did our kitchen and used it at the thresholds as and when it was needed.