Previously: #20594 (comment)
Possibly related to: #19536

Steps to Reproduce:

1. (Prerequisite) Use Internet Explorer
2. Navigate to Posts > Add New
3. Insert a paragraph with some text
4. Press Enter to insert a second paragraph
5. Press Backspace to delete the second paragraph
6. Note that the caret selection is placed at the beginning of the first paragraph

Expected Outcome:

Caret selection should be placed at the end of the first paragraph.

Additional Context:

This is working correctly in WordPress 5.3.2 and, as such, is flagged as "Regression".

cc @ellatrix