The hint is showing Siegfried E Unger instead of Mary Agnes Ruskauff
Something did go strange with the hinting engine there. There is an easy way to correct the source to the right person. On the right hand side, in the blue bar, click on Change then choose Seigfried:
This will get the source to line up properly so you can attach it:
After you attach it, it should disappear from Mary's page. If not, then just mark it Not A Match.
Thanks, that worked! I was previously trying to click the Change on the left side, but that wasn't changing anything.
The change log shows that a bunch of sources were cross-linked. That causes the hint tool to offer additional cross links. Whenever I see a wonky hint like this, the first thing I do is check all the profiles for the family and detach any sources that are cross linked.
By cross linked, I mean a source for the wife is attached to the husband, and vice versa.
For what it is worth, I never attribute such mistakes to contributors. More than once I have attached sources to profiles only to see FT reverse them. Ie, transient software bugs.