Just to confirm, are your subs reporting that no notifications are being sent? Also, could you check with subs if it's happening for desktop, mobile or email notifications (or all of the above)? Let us know and we'll take a look.
Noted. Have you selected "Publish to Subscriptions feed and notify subscribers" before publishing your videos? Also, could you check if your subs have 'Push and email' selected under advanced settings: https://goo.gl/VjLrAV ? Keep us posted.