I've never had this issue, or really any issues with Deadlock performance. I started a match and was DC'd over and over again. Restarted steam, then pc, and then my game wouldn't launch with 98% cloud update error. Then, a matchmaking ban on top of it all.
Alchemical fire should be red when the enemy team uses it, and should remain purple for friendly. Having no way of telling if it's friendly or not isn't ideal.