Am I crazy? I swear that with both the SMG and hand cannon overload shot versions that require multiple hits that it sometimes just flat out doesn't work, no matter how many hits you get. This seems to happen after you have stunned an overload champion once and are attempting to stun them again. The overload shot buff on the left never bothers to pop up despite hitting with a full magazine sometimes. This is especially frustrating with solo master-level content because the margins can be very thin for those overload champion kills (especially when soloing under-level). The margins are fine though, as long as the overload shot actually works...