This might be a ridiculous idea , but have you tried to re-launch Obsidian on your 2nd device once it has synced and before trying to open the workspace ?
I’m not an Obsidian Sync user but I think I’ve read somewhere that for some changes to appear, sometimes, a re-launch could be necessary (I just don’t know which changes exactly are concerned by a reboot of Obsidian … and it could also depend on the type of device)…