A non-breaking space is saved after adding and removing a space

There are two ways to reproduce this. First:

• Create a page with this content: "one two"

Then either:

• Place the caret before 't', press the Space key and then the Backspace key

or:

• Place the caret after 'e', press the Space key and then the Delete key

In both cases the result is: "one two", while the expected result is "one two".