Loop items' layout messed up in template preview

Hey team, I think this is a bug with a very low repro rate, it might only occur on my site and might be due to some misconfiguration.

However, it does seem like something is off with the way loops are rendered when using a page that contains them as a template preview. In fact, other parts of the same page are also rendered incorrectly, with collapsed paddings/margins.

Here’s a video showing my blog page, and my blog page rendered as a template preview:

I’ll be happy to make you a user account on this build if you’d like to check it out yourself.