Off duty schedule

Does anyone know why my off duty schedule stopped producing at the normal rate? I didn't change anything in game. I'm wondering if it has something to do with my phone occasionally being in airplane mode or low power mode? I used to get around 1,200 gold every 4 hours. The last couple times I opened the game I had been gone 8+ hours and each time I only got about 300 gold. I'm stumped.