epson powerlite 8100 killing lamps

Put a new lamp in and it only lasted 124 hours before the projector suddenly shut off with the lamp indicator flashing. No onscreen warning. Put another lamp in and it lasted less than 30 hours before doing the same. I've been using the same replacement lamps, bought from the same place for 7 years without any issues. They are not official epson lamps. Any suggestions would be appreciated.