How can we reproduce this bug?
SCSS:

$button-padding: (
  tiny: 4px 16px 4px 16px,
  small: 4px 32px 4px 32px,
  default: 4px 48px 4px 48px,
  large: 8px 60px 8px 60px,
);

HTML / INKY:

<center> 
    <button href="#" class="secondary">Book your free place today</button>
</center>

What did you expect to happen?
The button renders like this correctly on all but the ones mentioned below.

What happened instead?
The button renders like this...

What email clients does this happen in?
Outlook 2007,2010,2013,2016 (On Windows, only)