Period of high demand and a limited number of shares since it is a closed end fund. Nothing funny about it.
They have the ability to buy shares also off the open market too. If it goes too low they will issue a buyback like some of the other ETFs.
Some posters (paid by shorts... I know the usernames from other sites over the last 3 years) are try to scare people by talking a div cut however since their top holdings increased their divs in the last year I am not too concerned about that.