Hi @joshf
Thanks for the bug report.
We are aware of this issue, but have just realised that we didn’t post about it in our latest article: https://www.advancedcustomfields.com/blog/the-night-before-gutenberg/
I’ll update that with a mention to this issue.
The WP 5.0 editor doesn’t have a space for the “High” location, so yes, you will need to change the position back to “normal”.
We will be working on a fix for this over the coming weeks.