This is an issue where 2 dimension terminators have been created, one with a symbol cell and one without, in a V8 DGN file.
When using Place Note, the terminator with the symbol appears thinner than the standard terminator.
The Unit settings in both the Dim Styles are the same.
This issue relates to the terminator cell scale height being unchecked (if ' Uniform Cell Scale ' is selected both are the same).
The issue can also be seen to be due to the graphics that make up the two cells, they have a different height.
To resolve the issue, you can either change the cells height to be equal.
In this example the tilde was scaled to match the arrows height and created a new cell.