RSS Feed Inconsistent Time Format - <pubDate>

Attempting to use MailChimp to send a daily email triggered by new blog posts. Today’s email failed to send. Here’s what MailChimp suuport sent back:

“When taking a look into that RSS campaign, it appears that it is setup to send daily at 7AM based on new posts to the feed. When a new post is made, we will take a look into the in the actual feed of the RSS. So long as the pubdate is less than 24 hours old”

I dug into my feed. I noticed format differences for . Here is what I see for the last few days:

Fri, 14 Aug 2020 02:39:01 GMT
Thu, 13 Aug 2020 00:00:00 GMT
Wed, 12 Aug 2020 00:00:00 GMT
Tue, 11 Aug 2020 00:00:00 GMT

The most recent post includes a specific time (02:39:01 GMT). Posts before that include (00:00:00 GMT). Updated “Channel Refresh Time” from 60min to 15min. No other changes on the site.

Why is the formatting for different?

Here is my RSS feed: LINK