WIRIS module interferes critically with Code Block

Problem/Motivation

We have recently run into a problem with Code Blocks like as inserted into CKEditor.

The core Code Block CKEditor plugin creates blocks of code as below...

<code class="language-python">
</code>

The critical problem that we have uncovered is that simply having either of the WIRIS CKEditor buttons present on the active toolbar, causes corruption of the <code class="language-xxx"> tag by stripping off the closing tag...

What is left over is then understandably, HTML as gibberish as illustrated in the screenshot.

No MathML edit necessary

Just to clarify, you don't have to have performed any kind of edit that relates to WIRIS Math-ML etc - but if you have an existing, working <code class="language-python"> </code> content, it will be corrupted and you will not be able to recover inside the CKEditor.

Manipulation of the text content?

Correct me if I am wrong but I've always understood that the whole point of Text formats is that they are OUTPUT filters so quite apart from the fact that the corruption is occurring, why is the module trying to permanently alter the stored markup?

Any ideas anyone?