It would appear that the Windows wallet (at the very least) is failing to pick up that it is on a fork. I have been on both the major forks over the last week. On the first fork, net weight dropped to 0.001 and the wallet was still ticking along staking POS like everything was fine. I rebooted it to fix the problem.
After seeing your post I checked my wallet and I see a net weight of 0.091, with the wallet still ticking along happily. I will reboot again.
In the past, the wallet used to pick up on this automatically and return back to the main chain.
RE: Gridcoin users: check your block hashes -> we just lost 36% net weight in 1h