Oh gosh, I can't think of anything that could be causing this -- thinking of missed keystrokes, or extra keystrokes, if using key shortcuts, thinking of missed menu items, thinking you might have more than just the text selected, and a few other things. But nothing really makes sense.
I'm stumped -- if PT's suggestion doesn't help....well, there's always looking at the SVG file, I guess. Just put some text in a file with nothing else, and upload, either as attachment to reply, or wherever you choose, and give us the link. Then we could investigate the real thing.
But I've got my fingers crossed for the resetting of the Prefs file.
