The other answers are most likely the correct solution (stiff link I'm guessing based on chain suck).

But just in case you are using the term Powerlink in a generic way...

 - Wipperman chains call their link "connex" and is directional, if you
   put it on backward it can cause these jumps. The Wipperman Connex
   linkages are reusable.
 - SRAM chains link is called a Powerlink and allows for easy connection
   and removal, but is not re-usable.

Also, neither should be used on a Shimano chain. You need a Shimano pin for a Shimano chain. I wouldn't mix/match the Wipperman or SRAM connectors with anything but the same brand chain.