There seems to be a quirk with the time slider on the flight setup screen? Sometimes it’s a solid blue bar (as in the pic), other times there’s a thin red vertical bar you have to slide. Both are quite tricky to grab/manipulate, more so the thin red bar.
I’ve no idea why this varies. It seems completely random, unless I’m missing something.
Currently on msfs-2024 but I’m sure the same used to happen in 2020.