Missing Champions?

Okay, so I was playing as Vayne and on the loading screen two of their people didn't connect (Or so I thought) When I got into the game everything was fine until I pressed tab and I saw that they were missing two enemy champions. Our Sona said she could see the two I was missing (Lux and Singed) but when I talked about the enemy Jax she said there wasn't anything there. I tried disconnecting and re-connecting however the Lux was still invisible, I could see her spells but I couldn't click on her or hear her sounds. Has anyone else had this issue?