I have had issues recently where I try to import the Simbrief plan and in the init window I only get a combination of both airports, e.g. KJFKKLAX in the "CPNY RTE" in yellow/orange letters (the plan when imported is in blue letters) - I noticed that if I wait about ten minutes before importing everything works. This never used to happen so there is some issue which is delaying the availability of the flightplan.