In 1.14 players are able to be forced into 1-block high spaces. This poses an issue when being tp'd and there happens to be a 1-block high space under the floor. Eg. When tp'ing back from battling the heroes in the Library of Flames in Dwarves and Doguns I, I kept ending up under the floor in a leopard-crawl position, which I could only escape via /kill or a teleport scroll. 1-block high spaces beneath tp destinations ought to be filled.