Form block: separators don't align consistently

[Nic-Sevic]

Steps to reproduce the behavior

1. Add a form block to a post
2. insert a few blocks, including separators
3. check preview compared to editor

What I expected to happen

separators should display as blocks and alignment should be consistent

What actually happened

separators show with no color on some themes (Purpose) and periodically show misaligned on all themes This was the case regardless of block alignment or width when set to default separator; dots and wide styles displayed correctly

Context

3951753-zen

Browser / OS version

Is this specific to the applied theme? Which one?

not theme specific

Does this happen on simple or atomic sites or both?

both

Is there any console output or error text?

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

Reproducibility (Consistent, Intermittent) Leave empty for consistent.

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

In editor:

In preview/live:

[synora]

Something strange is definitely happening with the Separator Block when it's nested within a Form Block. Here's what my test looks like within the editor:

When I preview the post, the Separator Block doesn't appear at all:

[ianstewart]

@jeffikus is this a theme bug?

[jeffikus]

@ianstewart if it's not theme specific or part of a range of themes like Varia child themes, then it wouldn't be a theme issue. If it is, then it needs to be logged in https://github.com/Automattic/themes/issues/new