This has been reported on the update thread, and I've verified it using both damage figures and Effect Duration +1 upgrades. In the same stage, when autoplay applied the effect it was N, and when I did in the next wave manually it was N+1.
I suspect this might be a side effect of this bugfix:
- Characters should not use the skill shards (or lack thereof) of other characters of the same type and tier
Please fix, it's affecting our ability to autoplay harder levels.