Essentially at some random point in games, turbo build stops working for people who are using controller on PC. It essentially acts as if your turbo build setting is off even though it is on, and it never works again for that game.
A lot of other people are having this issue as well: https://www.epicgames.com/fortnite/forums/bug-reports/battle-royale-aa/1126646-turbo-building-stops-working-halfway-through-games
I'm going to try to look for a video right now and I will post it here if I can find one, but this is becoming a huge problem for controller on PC players.
Edit: here's a video on it. https://www.reddit.com/r/FortniteCompetitive/comments/bkmvue/no_turbo_build_when_using_controller_on_pc_in...