From a quick look at the file, I think it's Chrome that has the bug.
In your <svg> element is an xml:space="preserve" attribute. This means that white space in text content should be kept, rather than collapsed. Your text itself is then set on a line of its own, with tabs in front of it. So Inkscape is centring the whole string, including the tabs, making the visible text appear to move off centre.
You can confirm that the tabs (and some trailing white space) are present by repeatedly double-clicking on the text until you get a cursor, then using the arrow keys to move it beyond either end of the text. Pressing Ctrl-A in this mode will highlight the whole string, including the white space, so you can see its true extents.
One fix is to remove the attribute from the <svg> tag, but you might still get caught out with carriage returns and other characters that might not collapse as you expect. A better fix is to change the code from this: