What is the origin of the word buisy?

it appears originally to have been a 21st century misspelling of the Word busy

which had evolved much earlier from the old English Word bisig

meaning careful anxious & occupied as well as busy

tho spelled with the letter u & without the letter i since the 15th century

it was never pronounced buzzy nor byouzy but only bizzy

& evidently has no actual connection with bees or buzzing