Got the same result. All unlocked items were gone.
But seems re-creating 1.save is the key. In my case, I successfully got all rewards by the following steps.
NOTE: You will lose all customized key bindings since those configuration data is in 1.save file. So you need to re-configure key bindings again.
1) Launch Uplay in online mode.
2) Deactivate cloud save synchronization if enabled (Un-check "Enable Could Save Synchronization for supported games" in General settings)
3) Go to "<Uplay-folder>\savegames\<user-id>", and backup "1771" folder, then rename "1771" to "grwbackup".
For example. if you installed Uplay client into C:\Program Files (x86), it is "C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames\<user-id>". Go to there, and copy "1771" folder to somewhere for your safety, then rename it.
4) Launch GRW, then check "unlocked xxx" message on the screen
If you can see "REWARD EARNED!" notification messages by Uplay, you successfully unlocked rewards.
5) Exit the game
You can find new "1771" folder in "<Uplay-folder>\savegames\<user-id>", so now you have "1771" and "grwbackup" folders.
6) Copy "1.save" and "1.save.upload" files in "1771" folder to "grwbackup" folder, then replace those files
7) Delete "1771" folder
8) Rename "grwbackup" folder to "1771"
Now you have new "1.save" and "1.save.upload" files created in step 4, and also the original save data files(2.save and etc.) in "1771" folder.
9) Launch GRW again, then check unlocked items in loadout and appearance
10) Exit the game. Enable cloud sync again if need
If Uplay/the game asks you, use LOCAL save files instead of CLOUD save files