Comment 2 for bug 1761197

I think some of this is expected with the syncing up-down of instance data from parent cell to child cells and vice versa. There's some incompleteness there as Surya explained that some instance_extra fields are populated in the child cell DBs and some aren't.

Besides all that, we do need to fix up the migration path for operators moving from cells v1 -> cells v2 to properly populate instances' instance_extra data in cells v2 cell databases.