yes that what i think, but strange when the test was run the next day no fault was detected at all

Lots of resyncs or noise on line should NOT corrupt the config or firmware.

You can get issues where the software is not 100% stable and lots of resyncs make OS of the router unstable, but a plain old turn off and on should sort that. Never seem one corrupt the firmware due to a line fault.

In reply to a post by bob12345:

yes that what i think, but strange when the test was run the next day no fault was detected at all

An intermittent fault perhaps?

..... other times will be okay for a bit, ping around 50 ms , speed about 2.3mb