If you're in a laggy environment (in my case, connecting to a tmux session over ssh - albeit on the local network, but over wifi) and type faster than fish is processing things, an <enter> after a command appears to abort the syntax highlighting process.
In this example, I typed in make followed by <enter>:

Naturally, the command starts off as not found and in red (m, ma, mak) but is located and turned to the regular command color as the command (make) is entered. I am hitting <enter> before fish gets a chance to update that, and the highlighter continues to display it in red.
If I were to pause for 100-200ms after typing in make before hitting enter, this would not happen.
If you're in a laggy environment (in my case, connecting to a tmux session over ssh - albeit on the local network, but over wifi) and type faster than fish is processing things, an
<enter>after a command appears to abort the syntax highlighting process.In this example, I typed in
makefollowed by<enter>:Naturally, the command starts off as not found and in red (
m,ma,mak) but is located and turned to the regular command color as the command (make) is entered. I am hitting<enter>before fish gets a chance to update that, and the highlighter continues to display it in red.If I were to pause for 100-200ms after typing in
makebefore hittingenter, this would not happen.