incorrect spacing in html read

Scenario

Here is a bit of HTML. It was written by gnumeric, then slightly edited by hand.

Here's how it looks when viewed in a browser:

In contrast, here's how it looks when opened by gnumeric:

Here's a patch that makes the bug go away:

Applicability

I'm pretty sure this bug affects all versions on all platforms. The relevant code has been unchanged for 15 years.

It mainly shows up when the <td> elements have multiple children. Not everybody does that, but I have very good reasons for doing it.