Bush 2023 dvd Player & DTS ?

Just bought Bush DVD player not realising it did not have DTS option However when playing DTS soundtracks Through my Sherwood amp i get a graphic on the screen saying no sound please pick another format but my amp switches to DTS and i get surround sound i tried it on my Queen DVD which does not have any Dolby only DTS or Stereo PCM and i still got Surround sound when DTS option selected.Anybody got any ideas whats happening and am i actually getting DTS or not.
Thanks for any help.

 

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