Scale Shot and Water Shuriken deal 1 extra hit more than they should, and it's sadly not just a visual glitch. Even when they hit 5 times in total, the moves just simply add +1 more damage calculation at the end.

Other multi-hit moves seem not to be affected, only those that have a secondary affect, like scale shot raising Speed or Water Shuriken giving priority.

Thanks for the report, I was able to reproduce this. Moving to internal