#2502785: Remove support for $form_state->setCached() for GET requests → caused forms not be cached for get requests which has led to the following problem that the form might get rebuild with different entity revisions.
Additionally there might occur different problem:
This happens because the form gets cached together with the entity only on the first ajax request.
Both problems occur only if the entity gets edited in the background between the form get request and the first ajax request, but will not occur if the entity gets edited in the background between the first and any following ajax requests.
We have to ensure the form gets rebuilt with the same entity the form was initially built.
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+1 issue for concurrent edits.
My entity is neither translatable nor revisionable, but fields that are not exposed to form display at all are overwritten in case ajax (file uploads, multiple values fields etc.) is triggered. This can be huge issue that can result in data loss.
I also think entity shouldn't be cached at all.
Let's say products stock is managed by external service, it will be overwritten if someone is editing product even if stock is not exposed to form edit.