Missing text

This happened twice the last week - when I open my current scapple document, the last entry is missing. I thought the document is auto-saving, isn’t it.
Did anyone else ran into this? Is there a way to troubleshoot this behaviour?
I like Scapple as a brainstorming tool a lot - but for now, I don’t trust it too much.

Scapple: 1.2
Mac OS 10.11.3