I fixed it with the Litmus Bulletproof Button. Should've looked this up in hindsight.
<!-- Start Button (Compatible with Outlook) -->
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="border:none;font-family:Roboto,Arial;border-collapse:collapse">
<tr>
<td style="padding:15px 0 20px 0;vertical-align:middle">
<table border="0" align="center" cellpadding="0" cellspacing="0" style="margin-top:0;margin-bottom:0;margin-right:auto;margin-left:auto;border:none;font-family:Roboto,Arial;border-collapse:collapse">
<tr>
<td align="center" style="padding:0">
<table border="0" cellpadding="0" cellspacing="0" style="margin:0 auto;border:none;font-family:Roboto,Arial;border-collapse:collapse">
<tr>
<td align="center" bgcolor="#fff" width="300" style="padding:0;width:300px">
<a href="https://www.example.com" style="padding:10px 0;display:block;text-decoration:none;text-align:center;font-weight:400;font-size:16px;font-family:Roboto,Arial;line-height:20px;color:#0077dd;background:#fff;border:1px solid #0077dd">
<p style="margin:0;line-height:20px;vertical-align:middle;text-align:center;display:inline-block;width:200px;color:#0077dd">
Get Deal <img src="https://d2z2x9m6jf98op.cloudfront.net/email/template/arrow-blue.png" style="vertical-align:middle">
</p>
</a>
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
<!-- End Button -->
Started a new discussion: Outlook 2013 anchor links are adding weird colors ( Outlook 2007 / Outlook 2010 / Outlook 2016 )
Started a new discussion: Any cross-client solutions for overlaying elements (imgs, text, etc.) on the edges of 2 element?
Started a new discussion: Where and how do you get test images for testing emails for Litmus Community?
Started a new discussion: The inconsistencies of @media queries for Gmail and Yahoo! Mail on Android devices
Started a new discussion: How to set image height in Yahoo! Mail while the "height" property gets stripped away?