Yes, THD and IMD measure a touch higher than the "picky folk" would like.
I'd be curious to see if this would change on better measuring gear or not, but I wasn't entirely surprised given the NFB2 measurements on here. That, and the AGD site has warnings all over it that non-feedback doesn't always measure well. Not sure if that's applicable here or not. If the newer AGD Wolfson DACs are further improved on this, that would be exciting.
IMD is actually decently clean overall. THD "cleanliness" depends on the filter used. At least it's generally just 2nd and 3rd order stuff that is a bit high. Subjectively, though, I think this DAC sounds pretty darn good despite the slightly high numbers in some areas. It also just does really well in some areas. For the $150 I paid, it's probably one of the best audio investments I've made in a long while!
Edit: Touching on how newer AGD Wolfson DACs might measure, the NFB-10.33 is specified to have
<0.001% THD with 1KHz sine at 0dB. If that's the case, and IMD follows, I would be very curious to check out one of the newer DACs. Though the NFB-10.33 is a DAC/amp combo unit, if that somehow makes a difference.