Unexpected Search Results

I have a simple search setup and in most cases it seems to be producing the correct results.

One of the searches I am having issues with is when searching the term D&O. I have several entries where this appears. Most of the entries have this term in a grid field. I have the field set to be searchable but for some reason the results are not returning any of the entries that I know have this term.

I only get one result where D&O exists in an RTE field, but none of the others. I can’t for the life of me figure out why the rest of the results are not being returned.

Is there some sort of inherent issue with an ampersand being in the search term that throws the search off? Or is something else going on here?

This is with EE 5.2.6.

Thanks for any help.