Please do NOT add images via the "attach files" box, as you are then forcing everyone to DOWNLOAD the file to view it outside their browser. Drag/drop the image files directly ONTO your reply box so other users can see them without needing to download unknown strange files. Thank you!
I've been experiencing this issue. For me, it seems to have something to do wtih me making adjustments to the path before I finish it. If I do that, it seems to be automatically converted to a shape layer instead of a mask layer. I've stopped making adjustments to the path when I first create it. Instead, I complete it, click off of it and then adjust it after the fact.