Hi Sybren,
We are working on your problem. I do not think that it is you getting distracted that cause the problem. Rather it is most likely an internal calibration routine problem. A few other users have had similar problems and with coming releases we are both trying to solve the problem explicitly as well as adding improved logging to be able to better attack the problem should it persist.
If you have a bit of patience, please wait for coming releases (I don’t know exactly when this fix is beeing rolled out but it is already somewhere down the line in our release process, my guess is a few weeks until it is ready for download.)
If you are in a hurry, contact our support and perhaps they can arrange with some special fix for you in the meantime.