this is a choir arrangement started in Dorico.
I have been copying lyrics between staves, sometimes it is necessary to double click a syllable to edit it and press space to go to the next one. However, playback will start on pressing space. This happens in some bars, in others not.
Is the project particularly large? It sounds as if Dorico might be struggling to keep up with your input, and it’s ending up processing the Space out of sequence with the Shift+L command somehow.