Please see this post for bug in 21

viewtopic.php?f=325&t=33287&p=230012&hilit=FA10#p230012

Occurring again in 22

See screenshots of attempting to sign Kevin Everitt to a minimum deal in FA9/10 for greenbay to then try and sign him post free agency he is not on the free agency list. However he is a free agent still and can be signed by another team:

I recently noticed this issue as well. At first I took it as the player having no interest in signing, but I realized it was correlated to having an unaccepted offer from free agency period(s).