It looks like you have some kind of “security” or “opimizing” plugin that strips quite a bit of important tag attributes, like href="..."
and onclick="..."
and even style attributes. It adds classes like amp-wp-enforced-sizes amp-wp-80eb17b i-amphtml-element i-amphtml-layout-intrinsic i-amphtml-layout-size-defined i-amphtml-layout
to links generated by wppa. See this page source fragment (download link):
<a class="wppa-album-cover-link amp-wp-58aba57" title="Download">Download Album</a>
that should read something like:
<a onclick="wppaAjaxDownloadAlbum(1, '6' );" style="cursor:pointer;" class="wppa-album-cover-link" title="Download" >Download Album</a>
And (the download spinner):
<img id="dwnspin-1-6" src="https://betatest.opajaap.nl/wp-content/plugins/wp-photo-album-plus/img/spinner.gif" style="margin-left:6px; display:none;" alt="spin" />
what has been ‘destructed’ into:
<amp-anim id="dwnspin-1-21" src="https://www.marcustibesar.com/wp-content/plugins/wp-photo-album-plus/img/spinner.gif" alt="spin" width="20" height="20" class="amp-wp-enforced-sizes amp-wp-80eb17b" layout="intrinsic">
<noscript>
<img id="dwnspin-1-21" src="https://www.marcustibesar.com/wp-content/plugins/wp-photo-album-plus/img/spinner.gif" alt="spin" width="20" height="20" class=" amp-wp-68ee6ca">
</noscript>
</amp-anim>
Please tell me what it is, so i can put it on the blacklist. Also: firmly erase that plugin from your server and never re-install it.