It seems that Google have had to go out of their way to index these sites. There used to be a hack to get at plain html content, which I used to give as a workaround to users wanting to scan Wix sites, but that no longer appears to work.
As someone with a background in website accessibility, this all seems appalling to me*.
But they're gaining ground, I seem to be seeing more support questions about scanning WIX sites. (and their *!^%$ advert that I have to skip before almost every Youtube video I watch. When is Yotube Red going to be available in the UK??)
Unless anyone knows otherwise (please, please tell me if you know), WIX relies on a/ providing its users with an xml sitemap for submission to Google, and b/ Google being able to render js before indexing a page (again, as an old-fashioned gal, something I heartily disapprove of* )
So... here's my best advice for scanning a Wix site using Scrutiny (Integrity and Integrity Plus don't have the necessary js option).
1. Make sure you have Scrutiny 7.4.1 or higher, which contains some necessary improvements to the js functionality. The most up-to-date version of scrutiny is always here.
5. After the scan, switch on the Target Size column of the 'by link' table and check whether any of the Internal links have a target size of zero (switch the Filter button to Internal to see this more easily). If an internal page has zero kb as the target size, then it may have timed out before the page had finished loading / rendering, which means that you may have an incomplete scan.
If that looks well then you're good to go with your data, which should be complete.