I noticed that quirk in the usual veg & flower schedule myself.Done by mid-june?? It isn't even flowering yet, and that isn't even six weeks away... Are you maybe saying done with veg and starting flower ?
Being an auto-flower it might start to show flowering any day now. That gives us 6 weeks of a flowering by June 18th.
And June 22nd is the first day of Summer, the longest day of the year. Has nothing to do with the plant being done flowering, just thought to mention it.