Whenever the anchor label is changed and the template saved, the td styles are altered and the mso-padding-alt style removed what destroys the layout : 

source : 

<td align="center" bgcolor="#0E113B" role="presentation" style="border:none;border-radius:0;cursor:auto;mso-padding-alt:14px 30px;background:#0E113B;" valign="middle">
    <div data-editorblocktype="Text">
        <p style="margin:0 0;">
        <a href="#"
           style="display:inline-block;background:#0E113B;color:#ffffff;font-family:Montserrat, Arial, sans-serif;font-size:16px;font-weight:700;line-height:1.2;margin:0;text-decoration:none;text-transform:none;padding:14px 30px;mso-padding-alt:0px;border-radius:0;"
           target="_blank">Find out more </a>
        </p>
   </div>
</td>

output : 

<td align="center" bgcolor="#0E113B" role="presentation"
                    style="border-width: initial; border-style: none; border-color: initial; border-radius: 0px; background: rgb(14, 17, 59);" valign="middle">
    <div data-editorblocktype="Text">
    <p style="margin:0 0;">
        <a href="#" style="display:inline-block;background:#0E113B;color:#ffffff;font-family:Montserrat, Arial, sans-serif;font-size:16px;font-weight:700;line-height:1.2;margin:0;text-decoration:none;text-transform:none;padding:14px 30px;mso-padding-alt:0px;border-radius:0;"
           target="_blank">Find out more</a>
    </p>
    </div>
</td>

AS you can see the original style 

border:none;border-radius:0;cursor:auto;mso-padding-alt:14px 30px;background:#0E113B;

is transformed to 

border-width: initial; border-style: none; border-color: initial; border-radius: 0px; background: rgb(14, 17, 59);

When ever the label is edited via the visual editor and the template saved.

Why? And how can that be avoided?