Posts: default posts that come with layout are timestamped in UTC but user posts are in local timezone

[worldomonation]

Steps to reproduce the behavior

Prereq. user timezone is not UTC+0.

1. Create a new site.
2. Select any layout. I used Stratford.
3. Once site is created, create another post.
4. Go to My Sites > Posts.
5. Open all three posts (2 pre-generated posts and your post from Step 3).
6. On the right sidebar, click on the Posts tab.
7. Check the published date for all three posts.

What I expected to happen

Published dates for all posts should be aligned with user's timezone.

What actually happened

Default/pre-generated posts that come with the layout are set to UTC+0.
User-generated posts are set to whatever timezone is set for the user.

Context

User scenario manual testing.

Browser / OS version

Browser: Firefox Nightly 86.0a1
OS: macOS Catalina 10.15.7

Is this specific to the applied theme? Which one?

Should happen on all themes.

Does this happen on simple or atomic sites or both?

Tested on simple.

Is there any console output or error text?

No.

Level of impact (Does it block purchases? Does it affect more than just one site?)

Moderate - this causes the Latest posts block to show unexpected ordering, as well as confuse users that live hours behind UTC+0.

Screenshot / Video: If applicable, add screenshots to help explain your problem.

Screen.Recording.2021-01-22.at.15.38.55.mov

[obenland]

This sounds like it's an issue with default content on new sites? @simison Is this something you're familiar with?

[simison]

Yeah, @ianstewart and I were considering to not add this demo-content at all since removing/editing it is confusing, which would make this problem to go away as well.

[jordesign]

@simison @ianstewart Keen for your opinion if this is a bug worth addressing as part of the Blogger Experience Pod?