I don’t think temps are “supposed to” be highest before bed. I believe that in both Eat for Heat & Diet Recovery 2, Matt says that the most common peak temp is late afternoon/early evening, and that a dip in the late evening is common. So, you fit the pattern. Based on my understanding of the advice, a snack in the evening would probably help keep temps up in the 98-range. If a snack (esp carby or salty) also helps you sleep better, that would be confirmation.
For myself, I got my midday temps to normal (and even normal-plus during warm weather) relatively quickly (from lows ~97.0) once I dropped all the paleo business and ate my grains. However, good early-morning and evening temps have come more gradually. I’ve now had a few good morning and night readings, but still working on it for consistency.