Only on Android 6 all my Buttons looks different. Even in Outlook 10 the Buttons looks i expected. I don't understand that..Or is this a Litmus Bug?

Here ist my Button-Code Foundation Zurb Email):

 <table class="button small-float-center"
                                                           style="Margin:0 0 16px 0;border-collapse:collapse;border-spacing:0;margin:0 0 16px 0;padding:0;text-align:left;vertical-align:top;width:auto">
                                                        <tbody>
                                                        <tr style="padding:0;text-align:left;vertical-align:top">
                                                            <td style="-moz-hyphens:auto;-webkit-hyphens:auto;Margin:0;border-collapse:collapse!important;color:#000;font-family:Helvetica,Arial,sans-serif;font-size:14px;font-weight:400;hyphens:auto;line-height:1.3;margin:0;padding:0;text-align:left;vertical-align:top;word-wrap:break-word">
                                                                <table style="border-collapse:collapse;border-spacing:0;padding:0;text-align:left;vertical-align:top;width:100%">
                                                                    <tbody>
                                                                    <tr style="padding:0;text-align:left;vertical-align:top">
                                                                        <td style="-moz-hyphens:auto;-webkit-hyphens:auto;Margin:0;background:#fff;border:1px solid #000;border-collapse:collapse!important;color:#000;font-family:Helvetica,Arial,sans-serif;font-size:14px;font-weight:400;hyphens:auto;letter-spacing:1px;line-height:1.3;margin:0;padding:1px 12px;text-align:center;vertical-align:top;word-wrap:break-word">
                                                                            <a href="#"
                                                                               style="Margin:0;border:0 solid #fff;border-radius:0;color:#000;display:inline-block;font-family:Helvetica,Arial,sans-serif;font-size:11px;font-weight:400;line-height:1.3;margin:0;padding:7px 5px 7px 5px;text-align:left;text-decoration:none">WEITERLESEN</a>
                                                                        </td>
                                                                    </tr>
                                                                    </tbody>
                                                                </table>
                                                            </td>
                                                        </tr>
                                                        </tbody>
                                                    </table>
Image