Well KiSS product it rather unstable ...
They are good but this is the one of their bigges problems - freezes and other things that usualy start to work correctly after complete powerdown.
But if you look on KiSS devices not as hardware but as software
they are OK.
Not to mention that KiSS slowly , in pain
but fixes them one by one in a time.
I have DP-500 more then 2 years now , and my God what a bad shape it was with first firmwares ...
Now it's more or less OK , the only time I have to reboot it now to fix functionality is after playing MP3s by network - if you put it in standby after that and then try to wake - menu is gone
Also KiSS known to create "funny" situalions - more then once they work hard on firmware , tested it for a long time and then make some last minute fix that brake everything and release with it without testing firs.