Does the dragon level you get from meat reset each reign?

Yes. Meat raises the dragon's Reign Level, and that level resets every new reign (an 8-week season). Everything you gained in level through meat (or through combat) goes back to the base at the new season.

Don't confuse it with two things that never reset:

• The dragon's Star Rank (stars)
• Its Habits

So at the start of a reign, it's normal to have to re-grind the level of your dragons. Meat is exactly what speeds up that re-grind instead of doing it all in combat.

Strategic takeaway: don't stockpile meat "for later" between two reigns — it (and the level it gives) belongs to the current season.