The sort by votes button disappeared after discourse update, v2.4.0.beta2 +326. I’m referring to the square button on top of categories/homepage (latest, new, unread etc.)
To confirm, I also tried the plugin on a clean install of discourse (no other plugin or customization, I installed discourse, then the plugin, the button did not show), same result.
I also noticed a weird behavior: first, disable the plugin, then open the forum on a different browser tab, finally enable the plugin. Go back to the other tab, the “Votes” button will appear, but you can’t click it, and once you delete the cache (I reloaded the page with F5) it’ll disappear again.
edit
After the last update to the voting plugin and discourse itself, the (sort by) votes button appear and works in categories. However, it still does not appear in the homepage.