It appears to be a new bug introduced to Windows 1803, triggered by long pathnames. Chances are that the second count isn't correct either--if you went down another level you'd probably get different numbers again. I had a file transfer fail due to lack of space because of this bug... Windows and I thought there was enough space for the files until we ran out of disk space part way through the transfer due to the original size of the transfer being incompletely counted because of this bug. We can only hope that this bug will be fixed whenever Microsoft finally gets around to releasing Windows 1809, 1810, 1811, 1812--or whatever the number gets to by the time they finally fix the critical bugs in the current release!
In the meantime, you can use a program like Treesize to correctly calculate the folder sizes. You should also open the Feedback Hub app and upvote/submit feedback regarding this bug to further Microsoft's awareness of the issue. Unfortunately, ever since the inception of the Insider program, Microsoft arrogantly fired their quality assurance team and has ignored the feedback of dedicated technical users and software developers like myself, choosing to go with their dummy, crowdsourced Insider feedback. But there is so much bogus, unfiltered, and duplicate feedback on that platform that serious issues go unnoticed by Microsoft for months and years, which is how bugs like this regularly make it to final release nowadays.
Speaking of bugs, I don't even see how to create a hyperlink in this revamped forum anymore! So here it is: https://www.jam-software.com/treesize_free/