In between sessions we managed to level up our characters. I decided to get suggestion spell now that we were level 3. After adding it into the spell list by dragging it over from roll 20s spell archive the spell save DC is NaN under the spell description. It now does this for all other spells in that game. After trying it with other spells the spell save dc at the top of the list then became NaN. I tried repeating it in another game and it does not give me the same problem. No other players in the game have the problem.