Unable to assign field groups to a column

I went and created a new content type and set it up like the one I am having issues with. I then added the empty field groups. I moved two of them into the left column, saved, and then added their children with only minor issues, and they stayed in the column. With the third field group, I moved it up into the header first, then saved, added it's children, then made some changes, then saved again. This time when I moved that content type down into the left column, and then saved, I got this error:

Notice: Undefined index: name in Drupal\field_ui\Element\FieldUiTable::reduceOrder() (line 228 of core/modules/field_ui/src/Element/FieldUiTable.php).
Drupal\field_ui\Element\FieldUiTable::reduceOrder(Array, Array)
array_reduce(Array, Array) (Line: 233)
Drupal\field_ui\Element\FieldUiTable::reduceOrder(Array, Array)
array_reduce(Array, Array) (Line: 108)
Drupal\field_ui\Element\FieldUiTable::tablePreRender(Array)
call_user_func(Array, Array) (Line: 376)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 448)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 574)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 149)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 656)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

The field group itself stayed in the column, but it's children moved back into the header region, still indented like they are under a field group (see attached image). If I move the empty field group back up to the header region, and re-associate it with it's children, the error will go away, but I will then be unable to move the field group into any other area.

Here is the configuration from the test content type so you can have it. Hopefully this helps.

Sorry that I haven't gotten back with you. I have been slammed by a major issue here at work. I'll try it out and let you know how it works.

Thanks for all your hard work!!!

I got the latest version of the 8.x.3.x branch, and I am still having issues. It looks like that the region is till be set to 'hidden' for all of my field group headers. It took some wrangling like moving the fields out of the group, and then moving the header, and the putting in fields back in seemed to be the only way that I could get it to 'stick' in any other region except for the first one.

Also, I have noticed that when I move a group header, when I drag and drop, the header doesn't stay put, it continues to follow the mouse up and down the field list. If I move the header back to where I want it, then click again, then it will stay put. Then there is a chance it may move back to the first DS column after a save.

I have attached the updated configuration file for your reference.

If I move a group inside of a DS column, and then save, I still get an error. The group header moves to the top region, and the content inside of the group stays in the region it was assigned to, indented as if it was still under the group heading, with the following error:

Notice: Undefined index: name in Drupal\field_ui\Element\FieldUiTable::reduceOrder() (line 228 of core/modules/field_ui/src/Element/FieldUiTable.php).
Drupal\field_ui\Element\FieldUiTable::reduceOrder(Array, Array)
array_reduce(Array, Array) (Line: 233)
Drupal\field_ui\Element\FieldUiTable::reduceOrder(Array, Array)
array_reduce(Array, Array) (Line: 108)
Drupal\field_ui\Element\FieldUiTable::tablePreRender(Array)
call_user_func(Array, Array) (Line: 376)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 448)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 574)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 149)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 656)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

I can move the heading back, but it can't have any fields under it. Then when I get it to stay where I want it, I then move the fields I want back under the heading.

I hope this helps!