Oh, rats, Moini! Reading that message, I was sure you would know!
Although I don't know what ng-bind is either, when I open your SVG file in a text editor, I see, I think I counted 14 ng-bind....I'm not sure if "element" is the right terminology. They are all within text....well if it was html, it would be text tags. But I'm not sure if that's the right terminology either.
According to w3Schools, ng-bind seems to be either related to, or at least used with, AngularJS (whatever that is, haha).
https://www.w3schools.com/angular/ng_ng-bind.aspMy best guess about the disappearing ng-bind nodes is that Inkscape just doesn't support that code. I suppose it's also possible that you didn't use it correctly, but I'm not even close to qualified enough to be able to address that.
Ah-ha! DDG tells me that ng-bind is an attribute. Here's a quote from the first search result
The ngBind attribute tells AngularJS to replace the text content of the specified HTML element with the value of a given expression, and to update the text content when the value of that expression changes.
So, Inkscape is a vector graphics editor which strives to support SVG/XML. To my understanding, SVG is sort of a subset of XML. Here's a page which lists all the SVG Attributes, and I don't see ng-bind there. So it seems reasonable to think maybe ng-bind just isn't part of SVG.
Maybe from this point, you need to work in a text editor, rather than in Inkscape? (That's my non-programmer, non-coder conclusion, based on my brief research. In other words non-professional comment.)
Edit
Moving this to Beyond the Basics board.