Wait, I fixed it.
For me, I had to stop the launcher from updating all the different builds at the same time, like the beta and test servers and have the launcher only update one at a time. That seems to have fixed my problem.
I'm not entirely convinced Sentinel needs a big rework. If their inherent power was fixed to not be clumsily worded and implimented that would help.
Or hell, just change it to what it sounds like, each subsequent hit on an enemy gets a damage boost, like up to 25%