LR Mobile update-Can't adjust old (pre-synced) photos

Hi,

I have LR 5.6 on my desktop and have just updated to LR Mobile 1.2.0 on my iPad (iOS 8 update).  I am now unable to edit any of the photos that were previously synced prior to the updates being installed.  The photos are there, but the adjustment strips are greyed out.  New collections synced post update are working OK.  I have reset the LR sync settings under my iMac system library files, but it makes no difference.  Any suggestions greatly appreciated.

Thanks,

Mark