From a week of gameplay I've calculated the 3* red evo rune drop rate in Battlefield and Underworld madness to be 1 in 88 rounds! Other runes may be affected but I've been trying for reds. This problem started when shards were pulled from the regular levels. This problem is as bad if not worse than when the shard drop rate was low since talismans provide most of the stats for a character. Fingers crossed that fixing this is on e devs agenda.