The first of Shakespeare plays predate the first published English documentary. It was uncommon for spellings to be inconsistent or change between writings to be easier for a particular audience (in this case, actors) to be able to read.
There were entire efforts put towards pirating the plays by writing them, mostly from memory. It’s believed that someone in the crowd creating a stenographic copy would’ve been noticed so this is a less likely explanation. The memorial effort likely involved both audience and actors. “Official” versions meant to direct the stage productions might have been smuggled out or lost and found.
I haven’t gotten to the part yet that connects to the standard versions we have today. Some official versions were released to correct the record on bad pirated versions. Sometimes theaters would sell official versions to shore up funds.
Maybe this would explain the multiple shakespeare theory as well as writing inconsistencies?
first published English dictionary
and
It wasn't uncommon / It was common