Correct. This is the only rational explanation for the inversion. There is nothing else to imagine about the negative (inversion). Whether the number is "gamed" or just a single statistic makes zero difference to what the market is actually saying about debt instruments: "we care about now than the future".
What is afoot, as you say, is clearly a lack of confidence in longer term markets resulting in a move towards keeping asset in cash. Or those strange commodities like gold.
I personally believe global markets are in for a rough ride very soon. Brexit is not going to help much either. DT is going to have no time for Twitter.
When the yield on the long-term note is smaller than the short-term yield, and buyers would still rather buy the long-term note, something is afoot.