Why does my Inkscape file display differently when I save as PDF?

First screenshot is the .svg file on my Inkscape workspace.
When I save it as a PDF (second screenshot) , one of the objects, the dark blue circle with a mask applied (from a png texture image) gets bottom half cut off.

Any thoughts why and how to fix it?
Thanks!

[/img] https://drive.google.com/file/d/0B--fVm ... sp=sharing[img]
[/img] https://drive.google.com/file/d/0B--fVm ... sp=sharing[img]

Hard to say without the actual .svg file. Possible due to a gradient opacity, I believe PDF doesn't support that.

Thanks for the reply. I used two circles, one for the background, one for the foreground with a mask applied. For whatever reason, any time I created the foreground circle (with mask) it had some transparency. I was not able to remove this transparency or couldn't figure out how to.
Here's the SVG file with a different color combo I was trying, but it had the same effect (bottom half of circle doesn't appear) is in original post when I tried to save as PDF.
Thanks for the HELP!

Here's the SVG file: https://drive.google.com/open?id=0B--fV ... UN0dHB2bms