It was a display error, I often met it, at first I felt very surprised and I entered the exchange to check but the value of that coin didn't increase, I don't understand why?
But I do hope that you understand how volatile this market is?
So there will be a time that the price will keep on jumping up and down because maybe of the continues buy and sell or trade that is going on. So you have to continue monitor your wallet and of course the tokens you have.
Right now though, it looks like almost all coins have been pumping because bitcoin is making a good run to $4k. It's good thing to see our portfolio grow, and we do hope this is the start of a bull run again.