Team Builder client bug.
When in team builder matches I've found that quite often when a support joins the team leader will not be able to see them unlike everyone else who can. it also used to happen alot with jungler's not so much any more though. It only lasts for the initial supportjungler but when you can't click accept on the support causing one of your team mates to leave because they think you're trolling it is quite annoying. please fix this whenever you have the available time please and thank you. Also feel free to comment below if this has happened to anybody else im curious.