unplug headphones plug in mixer from headphone jack disables audio and score

1 Disable internal speaker from windows 10 sound settings
2 Make Preferred output to Headphones in windows 10 sound settings
3 Set Audio Output to Sound Mapper from musescore preferences
4 Plug in Headphones
5 Open a score
6 Play the score and listen in Headphones
7 Pause score
8 Unplug headphones
9 Plug 1/8" to R/L RCA into mixer/speaker set up
10 un pause score/or return score to beginning

No sound - No indication that score is playing

In order to resume sound and score playing you must save and close musescore then re open program and score