The BONAP map doesn't show Bidens laevis occuring in Michigan, but there are several observations of it Michigan on I naturalist.

Thanks for the research. I was all ready to call it Bidens laevis until I looked it up and didn't see it recorded/listed in Michigan, although the USDA shows it on the southern border of Michigan. Wikipedia just makes a kind of general statement of range which I guess could include Michigan - "It is native to South America, Mexico, and the southern and eastern United States." https://michiganflora.net/genus.aspx?id=Bidens doesn't record it either.

It looks like Bidens species, but it's odd that there are no serrated leaves in the photos. Did the plant have any serrated leaves at all? Most asters have serrated leaves lower on the stem, and smoother leaves near the top where they flower.

Here is a cropped and enhanced photo from the whole group of plants that does seem to show serrations on the leaves.

I did find the page in your screen shot after you mentioned Inaturalist. And yes, 3 of them are quite close to my sighting which was only a few miles NW of Holland, Riley Trails County park. I never saw them in this park before, not until the corner of the lake dried up and this group was growing on the dried up mud that would have been the bottom on the lake. Maybe the seed got into the water and settled out and sprouted? The group was about 3 feet by 8 feet.

These Bidens species have seeds that need special conditions for germinating, temperature, water level, etc. For some reason it hasn't been vouchered in Michigan, and that's why it's not listed as one of the states where it occurs.