Whitespaces are being ignored during copy/paste

Hi everyone,

I have an issue with my blog, which I noticed after I updated to 4.8.

I have a technical blog, and I often paste commands outputs samples to my post. Recently my editor started ‘ignoring’ my formatting – with whitespaces/tabs characters during pasting the output. To give a better understanding of my issue I have recorded a short video:

Do you suffer similar issue with your instances? I’d appreciate all suggestions.
I’m using TinyMCE Advanced, which I also updated to latest version (however when I observed the issue, my plugin was still in older version, so this ‘plugin update’ was not definitely a root cause).