I have asked this question over in GDSE, previously, but didn't really get an adequate response for the issue.

https://graphicdesign.stackexchange.com/questions/138125/ungrouping-and-moving-groups-in-inkscape-seems-to-cause-anomalies

Basically I'm attempting to transform shapes but with the Optimise setting enabled in the Preferences menu.  I abandoned the attempt mentioned above, in favour of a PNG alternative.

The problems that I'm encountering is that simple stuff, such as rotating a simple 90° 'L' shaped angle through 45° causes the shape to deform, as below.

The shapes I'm producing are so simple that I shouldn't need to add extra code, such as a transform, to the SVG code.  Is this a known bug with the optimisation feature, or as designed?

Seems I´m not able to find the issue you describe. Can you upload an affected file?

Okay.  I think I've found the issue.  After checking the XML in the XML Editor, there are numerous snapping options set on the <sodipodi:namedview> tag.  Once I've cleared the options (set them to 'false'), everything works as it should.

I'll take a look at the template for this and remove all of the unnecessary snapping.

@Polygon - Thanks for the pointer (yep; it was in the file).

Snapping doesn't seem very likely.