I've got all the services enabled, "icons only", sharing label: "Share this:"; all four options on "Show buttons on" are checked; likes are "turned on per post"; "Disable CSS and JS" is unchecked.

As an additional test (for possible recreation and comparison/contrast) I'm also using a plugin called Syndication links [https://wordpress.org/plugins/syndication-links/] which generally hooks in between Jetpack's "Share This" and "Related Posts". I'm using the default display "Syndicated to:" which is followed by several social icons. When I syndicate to Tumblr, similar to the "like" functionality from Jetpack described above, I also often have the text "Syndicated to:" displayed on the post, (but without the icons as I believe they're SVG's which reside somewhere else).

(As an aside, functionality like Syndication Links would be a cool feature for Jetpack to add/acquire, particularly if the "Publicize" functionality could hook into it and automatically pull in the links where the content was shared.)

Thanks @jeherve!