Failed to publish model on a scheduled refresh

Good morning all,

I have a bit of a mystery on my hands. I recently upgraded my PowerBI service to the September 2021 release from May 2020 release. We use the on premises version of PowerBI as we have an enterprise license. Prior to the upgrade, all refresh schedules were working with out issues. However, after the upgrade I am noticing that we are getting intermittent failures on the scheduled refreshes saying that it failed to publish the model. 

There is nothing in the logs showing why this error would occur nor does it happen all the time. It's random and sometimes it refreshes and other times it does now.

Steps taken already to try and correct the issue:

1. Stopped PowerBI service on host machine before upgrade.

2. Stopped and restarted PowerBI service after upgrade.

3. Opened the report in PowerBI desktop to make sure they refresh there, which they do.

4. Cleared the permissions on each data source and re-entered the credentials.

5. Deleted and re-created the subscription schedules.

I do notice that when the subscription is going to fail, the host server does not kick off the Microsoft Mashup Evaluation Container service on the host server. The below screenshot is of a subscription that is actually going to succeed.

Below is showing how some subscriptions succeeded and and another failed on the same dashboard.

Im stumped and if anyone has ever seen this happen it would be a great help!

Thank you!!