I agree that the slight drop in difficulty means nothing in this short of a time frame. Even your chart shows we are back to what, the March 20th hashrate? I do not call that a drop at all and this "fluctuation" could be anything.

Also notice the highest ever hashrate at the top, 270957.8644 GH/s was recorded on Monday, March 26, 2018, 4 days ago, not really anything to write home about,

Wake me up when hash-rates are back to pre-January levels, or at least it hasn't risen in a month, that will be the type drop off I will want to know about.