I ran into this same situation while helping family caught up in this strike. Logging in to Manage My Booking with the PNR did not show an itinerary. However, on the top where it allows you to download ticket receipts, I saw a new ticket number for the rebooked segments. Typing that ticket number into Lufthansa's receipt search showed the new itinerary (granted, it only showed the rebooked segments and not the uncancelled unflown segments). But the family was able to check in properly at the airport and get boarding passes. I'll attribute the blank website PNR to bad IT. Maybe she's already been auto-rebooked?