See this news report, with a very odd decision of the court:

“This year’s primary elections will be open as usual, Lamorena said, because he is convinced, after reading their bylaws, that the island’s Democratic and Republican parties welcome all voters in the primary, whether they belong to those parties or not.
But in future elections, the Guam Election Commission must contact the chairmen of the island’s recognized political parties to determine whether they continue to support open primary elections, Lamorena ordered.
If any party decides to hold a closed primary, then the primary election will be considered closed for all political parties, and voters must declare their party affiliation before receiving a ballot, Lamorena ordered. The ballot they receive would be for that party only. “

Usually, the jurisdiction’s laws would prevail unless a party objects. I have never heard of asking for permission from the parties before enforcing a law. Stranger still is the idea that if one party wants a closed primary, it is closed for all. That itself wouldm appear to violate the constitutional rights of parties that want an open primary.