@Vanguard3000:
The changed code appeared in Sigil version 0.9.2 in December 2015.
Indeed, prettifying your example produces spaces, but this happens naturally – by condensing white spaces, of which only one remains, just the one after the <br/> tag.
If Sigil were to prettify such a code:
Code:
<p>Test<br/>continuation</p>
to:
Code:
<p>Test<br/> continuation</p>
... You could think of it as inserting "unnecessary" space.
So you just need to remove these spaces yourself, and another prettifying will not break your code.