update to 14.4 has decreased volume to half on streaming to chromecast

Yesterday i Update Booth my iphone 8+ and iPad pro to 14.4: surprisingly the volume halved when streaming Music and or eg YouTube from either to the chromecast ultra on my amplifier. I have used this setup seemlessly for a Long time and through the many iOS Updates. (i I have to turn the volume up to the double)! ( No change on the volume which is reguleted on the eg iPad to the Bluetooth earphones) . Apple support was Quick to say that it is a problem that the Chromecast is not yet updated to the 14.4, but it has never been an issue with the many earlier iOS updates, so WHY now? Can we expect a 14.4.1 to correct this?