I was playing on a minehut server and I wanted to test out the new glow lichen on my house, but when I tried to put it in my inventory, it turned to stone. I found out after that if I replaced the stone with the 1.17 block it would turn back into the 1.17 block, but when I tried to place it down, it would place stone instead. This is true with all the other new blocks added in 1.17. It's fine in single player, though.