Comments in Review 360 from earlier versions not showing in current version.

Hi, Comments in Review 360 from earlier versions are not showing up in the current version. They usually do - any ideas why they are not?

I tried outputting a .pdf from the earlier version but it only shows comments on the current version. Is there any way to import comments from an earlier version in Review 360 into the current Review 360 version? All are on the same link.

Many thanks for any help.