For what it's worth, I have ridden from the UK to Poland and then back to Switzerland during the last 72 hours, and I have noticed that all four GPSRs that I am using (a BMW Nav III, a Garmin 2820, a Garmin 496, and something else) have occasionally encountered a lot of difficulty getting an initial satellite fix.
My guess is that maybe one of the satellites has run out of gas, or the American military (the folks who run the satellite constellation) might be doing some kind of maintenance on it, or maybe there is some other factor (solar energy storm, whatever) that is causing the problem.
I quite doubt that the problems are with the GPS receivers... especially considering that all these receivers (and yours too, probably) were working just fine last week.
Michael