So far we haven’t been able to figure out what path the LayOut file was looking at. Apparently it isn’t looking at the copy you were actually editing. Once you’ve relinked the file it should go on as normal.
The path in the LayOut file you shared is not pointing to your LayOut Drawings folder. It’s pointing to a file in a “cache” folder. I expect it’s the temporary folder SketchUp uses when opening a file directly from your Trimble Connect storage.
Going forward, if you choose to open your file from Trimble Connect you should use Save as and save it over the version already saved in the folder you saved the original. Subsequent saves of that file will go to that folder and if the LayOut reference is looking at that location, it will update to show your changes.