Changing weight of text note not consistent

We have a file from another firm in which we need to change the weight of text in notes which were placed in the file.  The notes were placed with a text weight of 0, and we need to change the weight to 1.  On some of the notes, we can simply use the "Change element attributes" tool, select the text and change it.  However, sometimes when applying the change this way, the text will "jump" to another location on the screen.  The leader remains unchanged and unmoved.  On many of the notes, we have resorted to dropping the componets to text and lines in order to make the changes.  We don't know which version of Microstation was used to create this file, and annotation scale is not applied to the model.  We are using V8i SS2 on 64 bit Windows 7 workstations.  What would be causing this behaviour?  Thanks.