Emails and notifications are not consistent

Summary:

We have created workflow objects to trigger emails, and we have also created server scripts to trigger web notifications. Recently during testing, we noticed that they are behaving inconsistently. One user is getting both the email and web notification, anther is getting only the web notification, and the third is only getting emails.

All three users are employees, and are creating SRs in the same fashion. This is with Redwood HRHD. We also noticed that on Monday one user was only getting Web notifications, then on Tuesday, only the emails were triggering.

Anyone run into this before? Everything was working correctly before the testing event.