There is a thread about this see link at bottom. Is Eunhasu working as it should.
A re-burn of the SD card will fix it if the SD card is healthy…this has happened to me a couple of times more often after firmware 4.22 last time I bought a new SD card.
SOtM also suggest that the 100/1000BASE-T and “auto negotiation” (settings in 4.6 firmware) can cause the sMS to go bananas.