It certainly sounds like an intermittent problem.
We aren't affiliated in any way with Voerwork so really can't offer you any advice that is specific. We are just a group of thermomix users who share ideas.
I noticed that you live in Queensland. Is it FNQ by any chance. One of our members had problems with cockroaches sneaking into her machine at night and destroying the mother board or something or other.
My advice would be too contact your consultant, or if you have no contact with them now call Head Office on
1800 004 838.
Please let us know how you get on.