I confirm that if you have a Custom Post Field, displaying conditionally related to another Custom Post Field, in a single Post edit screen all works fine.
You will fill the field "Trigger" with the right value and then the Field "Shown conditionally" will show as soon you click outside the just edited field.
When the same 2 fields are present in the Child Post Table within a parent post edit screen, the situation is different, for several reasons.
There is a table, and we cannot hide the entire Table column (there might be fields that conditionally should show and others not) That is why you will see the column itself always, no matter what.
Now, testing this with a simple field, I do not see the field that should be hidden in the Child's post table. I see just the column, but not the field, as long it should be hidden.
Every thing works exactly as expected in my tests, even the requirement of the field is not presenting any issue.
Now, you shared some links to the backend inviting me to log in, but I miss the log in details.
Now, I confirm that hiding an entire group by conditions of fields in another group, fails in that edit Child Post Table.
But this is also expected, due to the same exact reason as above.
You cannot hide all the column's content for that field group (there might be some that need to be shown)
Hence Types simply handles only field-depends-on-field conditionals here, not group-depends-on-field conditionals.
You can set conditional to hide single fields only, but not the entire group, in that Child Post edit table. Eventually this image will clarify this: hidden link
In case this does work differently on your install, please let me know.
Also - the entire post relationship is revamped and I need to consult with the Developers how much will be changed in that child post table (its a lot) - it could be that the issue will not even be replicable anymore as soon the new many to many relationship features are released stable, because the entire GUI changed.