This is an Obsidian sync limitation. Licat knows and will provide a solution in due time. For the mean time, I have implemented a workaround solution that was published yesterday in Excalidraw 1.0.10. The solution involves creating a parallel cache of Excalidraw files in a sync folder using markdown files. These files are synced and converted back into Excalidraw files on the other end. It is a slightly messy temporary solution, but so far, based on my testing, a reliable.