I agree with papampi, your rig is not idling, it crashed a lot in a row up to the point it rebooted, then it crashed again after 8 hours and so on.
The crash is from claymore miner, coin autoswitching has no issues, it just switches to NICE_ETH then one of your 1080ti crashes while mining on ethash.
If you exclude ethash coins from coin autoswitch you should be able to workaround such situation until you fix that card.