I'm trying to work with a sub theme and setting the default provided sub theme broke the top header menu.

https://monosnap.com/file/h80QQjSFYGJqnmqoKAh3vVrO1GEMKU

It appears this is due to using the block id of #block-callus for the styling. The sub theme gives that same block an id of #block-evolve-sub-callus causing the styling to break. I'm guessing this also applies to other areas as well. Any recommendation on how this can be avoided?

Yeah this appears to cause issues anywhere the base theme uses the block id for styling. Another example is the breadcrumb.

Thank you for your finding. We will check and fix it asap.

Thanks!