Jen, welcome back to running!
I would not worry about the color coding in TP. It just means that your predicted TSS was lower than your actual TSS. Because our plans use zones, you have a broad range of intensity to execute your workout. A Zone 2 hour run could have anywhere from 40 to 60 TSS, from lower Zone 2 to upper Zone 2. Both actual TSS values are correct, one athlete just performed the workout at the low end of Zone 2, the other at the high end.
TP tries to predict your TSS (and it does not adjust or learn, it’s a static predictive formula) and if it guesses wrong, you miss the “target” and it changes the color. Further, TP does not use the same formula for Pace and HR, so you will never have the same predicted TSS for HR and Pace. So, the problem is not you, the problem is TP.
Just pick one or the other and ignore TP. In fact, I’d turn off the color coding for TSS altogether.
David