I learned the above lesson a few years ago in the community, I kept overlooking the asterisk in the HOH requirement and flowchart that allowed a divorced or separated parent to claim HOH without  claiming the child as a dependent.
For any of you old enough, the IRS changed the definition of a qualifying child a few years back....before that change a child did not have to be a dependent to claim HOH as long as they were in the same household a parent could claim HOH status....loophole.