Wonky Text

Hi guys, just pumping out some stuff on my newly acquired olivetta lettera 32 and noticed the text is wonky sometimes, and i havent used the shift. Just wondering if its a symptom of something. It doesn't seem to be with any specific keys, and also the ones that are wonky as shiwn here, it seems intermittent. Hopefully its a quick fix, or something to do with my technique? thanks 👍