I have a couple of 317s behaving in the same strange way for 2 things I have seen. They are in different locations and run 6.45.6.
Important is that I have at least 4 units with the same symptoms as below so I think they might be related and caused by software or some issue in hw batch.
1) Free space is low but no files on flash.
I have tried the fix space npk but no change.
2) High temperature reported but ambient temperature is ok.
CPU load is 0%
We have been on site and its not too hot in the rooms.