"Finger-tight" is when you feel a slight resistance. If you are backing off from that where you can "wiggle" the lid, it is too loose and could cause similar or other problems.
Pressure canners must be allowed to come back to room pressure naturally -pressure is zero in the canner -- and should never be rushed like it is often doNE with a pressure 'cooker', but the internal temperature is still super hot (above the boiling point) so the authorities have made one change to what is printed in most Ball Blue Books and that is to wait 15 minutes
after the pressure regulator is removed and BEFORE the lid is unlocked and removed, to allow some of that heat to dissipate that might cause a catastrophic purge when hit with the room temperature. Even then you have to keep the jars away from drafts when they are moved to the counter for cooling off since the contents may be seen still boiling inside.
Despite all the little details that takes us awhile to get comfortable with, it is nothing to be scared about. A little nervousness is normal, but keep the smile on your face and all that good food you are preserving.