I am using the new, shiny public build with no code changes (last built with 3319). The crashes occurs as the rewarded video finished playing. Tested with 2 apps on 4 devices(Nexus 7, Samsung Note 3, Samsung Note 10.1,and Blaupunkt Soundfone S1) with 2 different OSes (4.4 and 6.01), all same result.
edit: Rewarded video is working as intended on ios
Cheers