Looks like they are running out of USDT. People are converting their BTC/Eth to USDT
People are trading and trying to make profits, but anyone who used eXch knows that this is only temporary.
Check their website later and you will see totally different picture... for example I can already see they have more than 56500 USDT now.
They also have other stable coins like USDC and DAI, so they are not running out of anything.
Look at their 24h volume and you will understand better
DAI 902491.92
USDT 204293.07
USDC 34601.15