Also R2 100K, will have a tendency, to attempt to turn the unit ON, at first power up. Because of its capacitance (and combined with the various transistor junction capacitances). Also, the various capacitances (stray), of the various transistor junctions.
So I can well believe it powers up, NOT in the way you want (presumably OFF is what you want, I think you said so, earlier).
These circuits (power on/off switch substitution) can be a real pain in the neck, to get them to behave as exactly as you want.
Some of these circuits, are better and much more reliable than other circuits. You are best, going for one of the reliable ones (which that might be, but I'm not sure off-hand. I think the reliable ones that work well, have more complexity to them).
I think there have been threads about it here, which could be a good source of better circuits and/or, later in that video you mentioned.