Custom Post Widgets' Content Blocks are displaying odd behavior in regards to it's interaction with the WordPress JetPack plugin's sharing buttons.
When embedded in a page, they don't show their own Sharing buttons, but it prevents the page's Sharing buttons from showing.
When as widget in a sidebar, the Sharing buttons show up at the end of the page content, as expected, but there's also a set that show up at the bottom of the widget itself.
I've managed to hide the ones in the widget just using CSS, but it's an odd incompatibility that should be corrected, especially where it's preventing the sharing buttons from showing on pages where they are embedded.
I think there's a way of having a post type properly register itself, so that JetPack sees is, and would let you globally exclude it from the Sharing Settings panel: