Is your Nucleus up to date? I think such an issue existed in earlier Roon OS versions but was fixed in Roon OS 1.0 build 254 last year:
Check your version of Roon OS on the web admin page of the Nucleus:
Roon OS should show version 1.0 build 254. Roon Server Software should show as 2.0 (build 1244) production.
If lower than that, you can update it right at the web admin interface as described in Update Nucleus Firmware from the Web Administration Interface on