Jerry, I had that happen to my sax player. In the middle of the song Witchcraft; he asked me what song are we playing.
Jazz was born by a musician getting a feeling and then expressing the feeling. No music, or charts as they call them were needed, because they knew the song. The age of different kinds of scales replaced feeling their way around the song; their solo was based on the chords and how they progressed. Those who knew used scales and arpeggios around the melody of the song; you still knew what song was being played.
Can you imagine listening to drum solos that used the same feel. I still remember trading fours, we were four men. When the drummer took a solo, we would leave the bandstand and return 15 minutes later. His solo included the drums, the bar stools, the glasses on the bar, the side of the entrance door -- he was a show all by himself. He never played his solo the same twice; he just expressed what he was feeling that night.
Big Band Jazz has to use charts, their solo, improv, never impressed me. Scales, arps. and modes are substituted in place of --- I hear it in my head, and then play it. That is the reason a musician can lose what song he is playing. I could listen to Errol Gardner (spelling) all day; each song has its own flavor.
Only my opinion, John C.