This history delay is variable, it depends on the day the server has, if it is more animated or depressed 
The other problem that has already been reported is that some sonoff mini devices send the values true and false for on and off, others send 1 and 0 and others both.
Yours must be the one sending both and the driver doesn’t know what to do with it.
They will have to add a subdriver to manage the on-off of this model since for the majority it uses the default
I guess they are very busy with other more important problems at the moment.