Pressing enter from a non-paragraph container doesn't give feedback of a new container being created

[rspeed]

Observed Behavior: While the insertion point is in a non-paragraph container, hitting enter causes the insertion point to briefly move down to the position of a new container, but then jumps to the right edge of the previous container. There doesn't appear to be a new container, but typing a character causes the insertion point to move down and a new container appears.

This behavior was not observed when the previous container is a paragraph.

Expected Behavior: Pressing enter would move the insertion point down into a new paragraph container.