This was noted before, and v5 didn't fix it. Briefly looking at the code, it looks right, so I'll have to dig into it a bit.

There seems to be a limit of nine color changes per font string. I couldn't find this documented anywhere, but it was consistent. There are two ways to solve it, the first is to use |r to return to the previous color instead of setting a new color, that doesn't seem to count towards the limit. The second way is to break up the text into multiple font strings to minimize the chance that a string hits the limit. The first way would involve going through all the locale files and changing every single quest, so I went with the second way. There might be a few quests that still hit the limit, but those can be fixed as they are found.