With the following wikicode for a table the first/left cell renders different from the three others:
```
{| class="wikitable"
|-
| line with <br /> …<br />
then a linebreak in wikicode
| line with <br /> …<br />without linebreak in wikicode
|
first a break, then line mit <br /> …<br />
and a second linebreak in wikicode
|
first a break, then line with <br /> …<br />and a second linebreak in wikicode
|}
```
This was tested in de.wiki and test2.wiki. I noticed this already much earlier in Commons in information boxes, but thought it would be a slight issue of the heavy used template.
This is about classical editing by writing wikitext, i. e. //not// about the Visual Editor, I actually do not know, how to test it with this.
Side remarks: `class="wikitable"` is only added for frame display, it happens without, too. `<br />` is added by the editor button. I know, that it gets simplified later.