Mogrts: Things put into groups don't stay there

If I'm creating a mogrt in AE, and "Add Formatting" > Add Group, and put some things in that group, when I export the mogrt and import it into PPro, one or more of those things are no longer in that group, which is rather annoying. I've tried using the release versions of AE (24.5.0x52)  and PPro (24.5.0x57) and the beta versions of AE (24.6.0x65) and PPro (24.6.0x75) but the problem is the same...well, I think it's slightly worse in the Beta versions - I seem to have two things "fall out" of the group, and it tends to be only one "fall out" in the release versions.

Here's the mogrt in AE:

...the "Growing Headline" checkbos is happily in the Headline group. But in PPro:

The last one or two things in a group tend to fall out of the group. Deleting the old mogrt from my library, then re-exporting the mogrt from AE, then replacing it in the timeline (and saying "yes" to replacing all occurrences of that mogrt in the project) does not change anything. I've tried adding random things (including comments) in and out of groups, but the problem persists.