notice anything?
Even though it is not posted, the site ONLY allows a specific minimum, however notice the value 'protecting' the lower value under it; also notice on the other side the same situation, these are perfect example of improper use of bots. Btw they stayed there for a prolonged period of time, so they are not simply spacer bots, or tempo bots, or tag bots, or notice bots, but shield bots to strongly encourage higher values on both sides instead of 'fair' trading by the actual traders.
Although, that could be a bot from the exchange, that is not the only explanation.
You can simply buy/sell 99% of an existing order, in which, case the remaining 1% would add up to a quantity too low to trade.
That was the reason given by the site, I have not seen much bot like activity at the site so I tend to believe that was indeed the case. thanks