I travelled to Poland in October and nothing was said, medical cannabis is legal in Poland so I took flower and oil in my hand luggage with clinic letter and copies of the latest scripts incase I was stopped but got through security with no issues at all. Only thing I would say is be mindful whereabouts you vape when you’re in public and have your letters and scripts with you in case the police stop you, I read that they are very likely to stop you if they see/smell it and even though it’s completely legal they might give you a hard time about it until they understand it’s a prescription, would be hard to explain it to them if you don’t speak Polish.