Snow Day Singed Poison Trail Invisible

During a game against Singed with the Snow Day skin on, one of my friends complained that he couldn't see Singed's poison. When I looked up to check out top lane, I also couldn't see his poison. He had it active, and was poisoning minions with it, yet the trail wasn't appearing on screen. He had this problem the entire game, while I had the problem for only the first 6~ minutes. Another person also said they noticed it, while the two remaining didn't experience the glitch at all.