Intermazed If you are going to use time-code stamps, it is important to read through the detail of using time-coded lyrics here - https://stagetraxx.com/docs/v4/song-details/lyrics/autoscroll/#time-coded-lyrics
The behaviour you encountered is called out "A single timestamp highlights all text until the next timestamp."
Now that can be a good thing, or a bad thing, depending on the outcome you are trying to achieve 🙂
The other important setting relevant to your situation is Highlight mode (ref: https://stagetraxx.com/docs/v4/settings/general/autoscroll/#highlight-mode)
If you wants to stay with your current process of just using a few time-code stamps throughout the song, but not have the current block of text change to the same highlight colour, you could try using Brightness as the highlight option. This will preserve all your text colouring.