Epix doesn't go into AOD after notification with 3rd part watch face

That will be quite the task because it behaves the same way for every single 3rd party watch face I have tried.

You are right. It is an issue Garmin should resolve. I developed a watch face and showed the same behavior.

After notification is cleared automatically, the watchface does not go to low power mode properly.

This is quite an old issue and I also wonder why this issue still remains.

Jinsuu said:

This is quite an old issue and I also wonder why this issue still remains.

Possibly because the developers of 3rd party watch faces have not been working with Garmin to resolve? I know there are some great developers out there who do actively engage Garmin Support through the Developer's forum but there are also others who do nothing except to pass the buck to Garmin. 

Dr Phil said:

Possibly because the developers of 3rd party watch faces have not been working with Garmin to resolve?

Actually this is has been already reported, as a thread on Connect IQ Bug Reports.

Receiving a (phone-)notification puts the watch face in a permanent low power mode with an update interval of 1 second - Connect IQ Bug Reports - Connect IQ - Garmin Forums

Status of the thread has been changed to 'Acknowledged', 

Also there is a post on the beta program report forum.

Low power mode problem - Public Beta 11.28 - Fenix 7 Family - Public Beta Reports - Garmin Forums

In this case the status of the post is 'ticket created', so it is natural to expect the issue will be resolved soon.

However, the issue still remains until Epix software version 13 betas.

Some developers already did what they could do, but the issue has not been dealt for 2 or 3 months.

I know Garmin has a lot of issues to deal with, but I hope Garmin to resolve this issue with higher priority since it drains the battery significantly everyday.

Good to hear that it has been reported to Garmin. No doubt they will work their way to a solution eventually. In the meantime, the solution for those experiencing this is to either persist with the 3rd party watch face or revert to one of the default watch faces.