If your application goes through, then you will most likely never see a citizenship judge, just take the test and do the oath. If it were refused based on you having PR in the US, then I think they would give you the right to appeal. You should call CIC and ask. The only thing I know of is that your PR status of Canada can not be in question when you apply for citizenship. If you have received PR of the US and moved there, somebody might say you are not intending to live in Canada anymore, however, the possible reasons they might take your Canadian PR away don't include getting a PR of another country.
According to the rules:
Permanent resident
46. (1) A person loses permanent resident status
(a) when they become a Canadian citizen;
(b) on a final determination of a decision made outside of Canada that they have failed to comply with the residency obligation under section 28;
(c) when a removal order made against them comes into force; or
(d) on a final determination under section 109 to vacate a decision to allow their claim for refugee protection or a final determination under subsection 114(3) to vacate a decision to allow their application for protection.
And section 28:
Residency obligation
28. (1) A permanent resident must comply with a residency obligation with respect to every five-year period.
Application
(2) The following provisions govern the residency obligation under subsection (1):
(a) a permanent resident complies with the residency obligation with respect to a five-year period if, on each of a total of at least 730 days in that five-year period, they are
(i) physically present in Canada,
(ii) outside Canada accompanying a Canadian citizen who is their spouse or common-law partner or, in the case of a child, their parent,
(iii) outside Canada employed on a full-time basis by a Canadian business or in the federal public administration or the public service of a province,
(iv) outside Canada accompanying a permanent resident who is their spouse or common-law partner or, in the case of a child, their parent and who is employed on a full-time basis by a Canadian business or in the federal public administration or the public service of a province, or
(v) referred to in regulations providing for other means of compliance;
(b) it is sufficient for a permanent resident to demonstrate at examination
(i) if they have been a permanent resident for less than five years, that they will be able to meet the residency obligation in respect of the five-year period immediately after they became a permanent resident;
(ii) if they have been a permanent resident for five years or more, that they have met the residency obligation in respect of the five-year period immediately before the examination; and
(c) a determination by an officer that humanitarian and compassionate considerations relating to a permanent resident, taking into account the best interests of a child directly affected by the determination, justify the retention of permanent resident status overcomes any breach of the residency obligation prior to the determination.
You can find those in the immigration and refugee protection act at
http://laws.justice.gc.ca/en/I-2.5/index.html
Immigration Forum
