Headings are horizontally breaking out of the view port on mobile

[connorhsm]

iPhone 7, Chrome browser.
The below can be seen on multiple headers with the same/similar styles, pictured is the worst one.

[XertroV]

thx. any idea if this is new?

Here are some old previews if you want to check:

• https://graphs-add-net-change.preview.flx.dev
• https://20200811-fix-spelling.preview.flx.dev

[connorhsm]

The issue is not present in either of those previews, no other info on when this became an issue.

Preview:

Current:

[connorhsm]

I want to point fingers at this commit, purely based on it seemingly being the more recent changes to typography.
I haven't had success setting up for dev to test this out.

This seems to be effecting all h1 headings, including a post that was just linked to in an email to all members.