Audio file inserted in Impress stops working after reopening a saved project

Hello. In libreoffice impress when I add sound files to a slide from the modify transition tab > Sound > other > and add one of my audio files the sound plays normally. The sound works fine when previewing slideshow. However as soon as I save and close the project the sound will no longer work when I open it again to work on it. Once i open it there is a small blue diamond icon that appears beside each slide that contains a sound file. If i remove the sound and put it back in the diamond disappears and the sound works until the next time i save and close the project. does anyone know why this is or what that blue diamond means

Same is happening to me. Anyone?