Had another look, if the camera height is 1.7, all seems fine. If it is a different height (lower in my case), I see the bug. When I play the shared space on a PC and Android Phone, I get the score text at a different height
Thanks for sharing the scene! The reason why the text element seems to change height in the play mode is because the camera item always tries to reach a minimum height of around 1.7m-1.8m when it is set to Walk mode.
So before your text has the chance to parent itself to the camera, the camera lifts to the minimum height required for the walking mode. Only then the CoBlocks code runs and the text item is attached to the camera.
Here are some fixes for this behavior
a) Adjust the scale of items in the scene to match the default height of the walking camera
b) Remove collisions on the camera
c) Set camera to Fly mode
Alternatively, you can parent the text item to the camera without CoBlocks like this: