I remember doing that!The leaking problem in the original PT was lack of wicking material. If you bought some 1mm silica and laid it right across the top so it stuck out both sides it didn't leak or take the usually 2 flavor wicks inside the head and set them so some of each stuck out the sides it didn't leak. Best fix was to remove the silica altogether in a new head and replace with cotton into the stock coil. The few PT heads that I did use before I rebuilt them didn't leak with that little bit of revamping the flavor wicks or adding the wick across the top.
Yes.. break the vacuum and they leak but that still goes for a multitude of attys still sold today.
I think Kanger fixed that when the revamped the coil heads. The old ones we called "stubbies." The newer ones you still get today have a longer shaft into the chimney and a different silicone rubber gasket.
I still have a few stubbies, I think...