Framing / scaling change with Unsharp Masking?

I'm pretty new to Premier Pro (20+ year Photoshop user) and ran into something unexpected over the weekend.  When I tried to apply unsharp masking to a couple of clips, the framing changed dramatically.  It looks to me that the image is scaling vertically at about 105 to 110% with the anchor point at the top of the frame.  So what's happening is that I'm losing what looks to be about 10% of the content along the bottom of my frame.  Unfortunately, I need that content.

I fully understand why effects such as corner pin and warp stabilize will result in the loss of content around the edges, but why unsharp mask?  Has anyone else seen this?  If not, I can do screen captures with the effect enabled and disabled and send them in another post.  But I the effect is very straightforward:  when I toggle the effect on I lose about 10% along the bottom of my frame; when I toggle the effect off that content along the bottom returns.

Would love to know what's going on, and would love even more to sharpen my output without losing the bottom 10% of my frame's content.