This has been an issue for a while now. Tag folders just error out become permanently inaccessible.
I assume it happens when an invalid data type somehow writes to the tag, but sometimes completely new memory tags with no value can cause this to happen as well. The biggest issue is that you permanently lose access to any branch folders that may also be inside the folder with the tag that caused the error.
There are no errors or anything at all regarding this issue on the gateway logs.
I’ve done everything I can think of to resolve the issue but it seems to be unrecoverable without just losing work by pulling a backup.