does anyone know why it happens, when I scale the view, the angular dimension breaks and even I can't redo the angular dimension.
Thanks in advance
This seems to be due to missing references, try recreating dimension and edges for bend as references. If possible share data that may help in investigation.
I don't know why the dimension is failing, it shouldn't be.
I would not dimension to the tangent lines. There is no physical feature to check this dimension after manufacturing or if there is, it would be difficult to physically measure.
The appropriate dimension would be: