Yesterday I started doing Spider with 7 Mystery shards and then did a few dozen runs (probably more) and had 7 at the end. To make matters even more odd I saw one run complete where it claimed I won nothing and I had super raids on, so 32 energy for nothing. I did not have auto sell on, I won quite a bit of gear, but definitely nothing close to the runs I made with the report showing no other rewards. 

Then last night I ran 37 Fire Knight runs and got, 37 pieces of gear, and nothing else. In both cases I did not receive a single shard or brew and in the case of spider I seemed to often be gettign nothing.