I believe its a malfunction  warning, but there are people here who will know a lot more about this than I do.
I had a similar problem before Christmas and the unit eventually failed but is now repaired.  Not complaining, used it almost everyday for many years. In my case the problem was:
The problem was that several electrolytic capacitors had leaked in the
SMPSU module and caused instability in the voltage regulation and the
ability of the SMPSU to deliver reliable voltage under load. In turn,
this stressed some regulators and resulted in the symptom you experienced.