Hi, just a guess, some things require a certain period to give stats, like it needs a fixed amount of data to interpret, sorry if this was a silly reply.
I agree with Fenn that it may need to colletc more data. BTW you say when you have signed-in? I never have to sign in. Once I have scanned the sensor with my phone it dispalys the reading and I can then go straight to any of the App options including graphs. Do any of the other options display such as HBA1C etc?