The front end shows a neverending "pulsing" red circle, hence I deactivated the Theme and used Twenty Seventeen.
In the footer Widget, I made sure the View "Themen" is shown.
On the front page or any other page, I see no issue.
Here you described no matter what, you see the problem:
https://toolset.com/forums/topic/view-outputs-password-field-and-send-button-on-a-protected-pages-footer/#post-619395
It seems thou according to your last information, that this happens only on password protected posts.
I can confirm this on the copy of your site.
The Current solution to it is, remove the Content Template Loop Item and instead add the code directly to the Loop:
[wpv-layout-start]
[wpv-items-found]
<!-- wpv-loop-start -->
<wpv-loop wrap="2" pad="true">
[wpv-item index=1]
<div class="row ">
<div class="col-sm-6"><span class="kb-footer-bs-item">[wpv-taxonomy-link]</span></div>
[wpv-item index=2]
<div class="col-sm-6"><span class="kb-footer-bs-item">[wpv-taxonomy-link]</span></div>
</div>
[wpv-item index=pad]
<div class="col-sm-6"></div>
[wpv-item index=pad-last]
<div class="col-sm-6"></div>
</div>
</wpv-loop>
<!-- wpv-loop-end -->
[/wpv-items-found]
[wpv-no-items-found]
<strong>[wpml-string context="wpv-views"]Keine Themen gefunden[/wpml-string]</strong>
[/wpv-no-items-found]
[wpv-layout-end]
This will solve the issue.
The problem is that you call a Content Template to style the post and 2 Loop Items (also Content Templates) in the View Loop.
These get overwritten by the calls to the first template, which styles the single post.
In my test, I had only the Loop items but no Content Template applied to the Content Itself.
Now I was able to replicate this:
1. Create a Taxonomy View of any kind
2. Make sure to insert a Content template in the Loop
3. Make sure to password protect a single post
4. Insert the View as Widget and visit that post
You will now see all the Posts from the View as password protected.
We have several similar issues with Content Templates replacing other the_content filter calls.
I will add this to that list so we can solve it as well.