Shared Blocks: Can't edit Paragraphs

[mcsf]

Description

After tapping Edit on a Shared Block that is or contains a Paragraph block, what is experienced as the caret jumping and/or the block being re-selected prevents the user from editing that Paragraph.

So far, testing on core blocks hasn't revealing another problematic block type (rich-text siblings like Quote are not affected).

To Reproduce

Steps to reproduce the behavior:

1. Add a Paragraph, add some text to it.
2. Save as Shared Block.
3. Select Edit on the Shared Block.
4. Try to edit the Paragraph block.

See screencasts below for a non-nested and nested situation. Notice in the nested situation how the Columns appender is also impossible to use, but the Latest Posts block is fine.

Expected behavior

Editing should happen just as for any block.

Screenshots

Single:

Nested:

Environment

• OS: macOS, latest High Sierra
• Browser: Firefox Developer Edition, latest