This has happened to me too. Ever since I upgraded to RC14
[DumaOS] process '//usr/bin/dpiclass' died restart:true,
This log pops up and qos & ADblocker fail to function.
Regardless of what you do this returns. No matter the amount of restarts/factory resetting. Even if you downgrade it still happens within a 6-12 hour window. I'm a long time netduma user I can say gladly there's a firmware most likely the intermediary or RC 14 that ruins the router. This is the 2nd xr500 that has been affected by this.
Might be time to return to the R series
Wish I still had my OL R1 thing was legendary.