The heliosphere is has been weakening slowly but steadily since we began monitoring it ~50 years ago, and the cause is the sun's solar wind losing temperature and density, and thus pressure. Whether this is an unusual phenomenon for the sun, or part of a cyclical pattern, is simply not known... a 50-year record for a ~5 billion year old star amounts to beans.
This weakening solar wind means we have a higher amount of galactic cosmic-rays entering the inner solar-system, which could cause problems for spacecraft and any humans who go to the moon or Mars, but since Earth has its own magnetic shielding and atmosphere, we will be quite fine.
Edit: It's also quite possible that the current extreme drop in the sun's magnetic field strength is related to the current solar cycle's minimum being more calm and long-lasting than usual. But there have been a few sunspots observed belonging to the new cycle so it's clear that it hasn't shut down or anything drastic like that.
