I wouldn't be too worried by it. From what I've gathered, Jeff has a lot of irons in the fire so to speak, so he may just need the income for some project or even to just maintain his lifestyle. He may simply just think of this whole platform as a hobby, and as such, a very inexpensive one that pays for itself. If he cashes it all out of course.

And thinking about it just from a good investment strategy, he certainly did buy low and sell high. Some of his early posts were getting over $10k payouts and as the price of Steem fell he continued to get similar levels of Steem even though its price had tanked all the way down to below 10 cents at one point. Now the price is 30x its all time low, which was less than a year ago, so selling now doesn't seem like such a bad idea from that perspective. It's also possible that he thinks we're in a financial mania and he's selling at what he sees as a peak and he wants to buy back in when he anticipates a significant price drop.