Oh no! Just to confirm, have you made sure you've selected "Notify subscribers" under advanced settings before streaming live? Also, your subs can check notification settings: https://goo.gl/giVA8o . Let us know.
Could you ask your sub to check their bell settings for your channel and see if they've opted-in to receive all notifications? They may be on the default setting, which is to receive notifications occasionally. Here's a guide to help check that: https://goo.gl/giVA8o (2/2)