The answer to that is, at this moment, no one is sure of anything. In theory yes it will be taxed in some form. You must maintain the 800k to keep the visa running.
There are new tax rules in Thailand, remittances into Thail are taxable, you will need to explain any remittance. If u say it's from work "anywhere" you will have your visa cancelled and deported, with the wrong type of visa stamp.
Ally, the damage has been done, the new rules are a disaster and many are seeing it. It says "come to Thailand and worry about your taxes" or "do not come ever"!