Bittrex used to be one of the best exchanges there is within the market, but now they are just simply getting worse by the day. Unlike Binance, Bittrex is not forced by any regulatory pressure for it to behave the way it is right now, so they are basically just screwing customers over and trying to play the long game for people to just give up and hope that they end up with the users fund.
It has everything to do with regulatory pressure.
A few years ago, everyone was using unverified accounts and withdrawing freely without regional restrictions. Basically overnight, unverified accounts were dropped to 0.025 BTC and 0 BTC daily withdrawal limits depending when the account was created. Then they're banning Iranians, Crimeans and others. Not long after that, they segregated US users from the rest of the world and pulled dozens of token markets from US investors, due to pressure from the SEC. Then came mandatory KYC for all users. Now, similar to Bitstamp, we're seeing increasing numbers of complaints about their enhanced due diligence policies. The list goes on. They're obviously reacting to pressure from the Treasury Department, SEC, FINCEN, possibly Homeland Security and others too.
Bittrex seems to be turning into the next Bitstamp/Gemini -- quick to freeze or terminate accounts, overly invasive AML/KYC/CFT procedures, etc.