Is deferring my mortgage to invest in stocks a good idea?

[Artie Butcher]

Hello Bigger Pockets! I'm a new member and first time poster. 
I'm 25 years old and have been living in my first home for a little over a year. My strategy is to 2 year live-in flip the house, and I've also been house-hacking (renting out a room). When the covid started popping off last month, I immediately put my mortgage into deferment with my loan provider. I'm still working my full time job with no changes to my paycheck, so my plan is to take the money I would be spending on my mortgage for 3 months and use it to invest in the stock market. On July 1st, I'll start paying my mortgage with the understanding that my 3 months of missed payments are pushed back to the end of the loan. Then in April of 2021, I'll sell my house and buy my next flipper with the equity from the sale AND my stock market gains.
My question is... is this a good idea? Is it a shady thing to do?. Are there any details that I overlooked or are there any reasons this idea won't work? I'm still very new at real estate so I'm unfamiliar with a lot of this type of stuff. Thank you for any input.