Reading Plans not appearing properly in the Logos app on iOS devices

I've just generated three new reading plans on my Logos desktop (running 7.8.0037 on Windows 10) - one was a custom reading plan while the other two were auto-generated.

They all appear correctly in the Verbum app on my iPad (this is running the stable release version 5.15.2) as shown below

However, in the Bible app (running the beta version 5.16.2) only one of the new ones (the custom plan) appears. (The Bible reading plan has been there since January)

But it's not just a beta issue - as I see the same thing (just two plans) in the Bible app on my iPhone which is running 5.15.2.

The Reading Plan documents are present in the app

But if I open one I get the option to "Generate Plan" but tapping that results in an error

Any insights appreciated!

Thanks, Graham