A rendered song is an audio file. Look at the Mixer. The bottom track <Audio> should be listed and populated with the audio file. It is below the Soloist Track and mine is orange colored. You are correct that there is no chords populating the Chord Sheet. Hit <Play> and you should hear the audio track play and see the meters registering. If the Style is enabled, you will also hear the Style play but it will only play the first chord listed in the Chord Sheet.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.