Just giving everyone a heads up, ESRI are aware that the recent AGOL update has caused an issue whereby web maps previously containing transformations are no longer assigned. You can confirm this by opening a web map in ArcGIS Pro and you'll notice that the transformaiton is empty:
I don't have any more information on this, but hopefully others can share their experience and some can also give updates on the fix timeline.
I would be interested to know if this is confined to certain transformations and SRSs. And whether we can hot-fix with AGOL assistant somehow.
UPDATE:
A regression bug, which is a bug introduced following an update, has been identified, fixed and logged with the appropriate product team. This bug has been attached to your case in My Esri for your reference.
- BUG-000172218
- Following the ArcGIS Online November Release Hosted Feature layers using British National Grid projection are reprojecting to 0,0
- Fixed
Please note: a manual clearing of the feature layer cache may still be required to see data in the correct location. This can be done by toggling editing on and off again on a service exhibiting this issue or by performing an edit to the feature data and retrying after waiting for the cache control time to pass (default is 30 seconds)