If you go to say 661 wrong word in marriage location and click ON it, it shows you what kind of errors that covers. Lets say you decide to do 1800-1899 years and click on the number 311 (which is how many there are) you get this report in a separate tab.
This gives you the profile link to fix it, what it thinks is wrong, name, religion?, birth, death, gender, privacy level, manager, marriage, and status.
Since this is a marriage category look at the info. "According is not a location" is shown. Now look under marriage. I see the date and HOLY COW, this person put a bio section instead of a location. THIS must be the error.So go to one of the 2 profiles, and edit the marriage to the other profile.
Now I would probably copy all of this into the wife's bio section if it isn't already there. Then delete out all the text that doesn't belong there leaving it blank. If there is any marriage info on either profile, see if it contains a place. Then add THAT location into the field. Note on the profile you put all that info into that you are fixing the marriage location under "Explain Your Changes".
Once you are finished for tracking purposes, hit the status button in that report and document what you did.
There will be some differences by type of suggestion but this is pretty much the same for all.
(BTW if someone has done something on the profile since June 3, 2018 they may have already fixed the suggestion.)