Weird spacing in multi-line equations

[EpicEricEE]

When using explicit equation environments (such as equation or aligned), the spacing around the equation changes when the equation has multiple lines. This is not the case when just using $$ ... $$. For example

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% Left side in image (this is shifted upwards)
\begin{aligned}
  a^2 + b^2 = c^2 \\
  a^2 + b^2 = c^2
\end{aligned}

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% Right side in image (this is what I would expect)
$$ 
  a^2 + b^2 = c^2 \\
  a^2 + b^2 = c^2
$$

Lorem ipsum dolor sit amet consetetur sadipscing elitr sed diam nonumy