Using less to paginate content (that either doesn't fit on a single screen, or would fit but -F wasn't specified) corrupts the colors of previous output.
Before:
After:
The prompts are drawn by oh-my-posh, which is configured to use colors which are not part of the color scheme selected in Windows Terminal. It appears that when less restores/redraws the previous output, it remaps colors to the nearest color from the color scheme.