Got this back from TS (posting in case anyone else ever has the issue):
“I spoke with one of our developers and they figured out that the issue you are experiencing is occurring because many of your dimensions were originally created using a dimension default that no longer exists in your plan file. Because of this, whenever your annotation sets change, changing your active dimension default with it, the dimensions using the non-existent dimension default don’t know what to be referencing and so switch to using the active dimension default. You can correct this for each of the changing views in your layout by opening the plan file from that view, select all of the problem dimensions, click Open Object, and then select the correct Dimension Default from the drop down menu, and click OK. By assigning the dimension default to the dimension object in this way, you will ‘lock it in’ and the dimensions will no longer change what default they are using. You can select multiple dimensions at the same time by holding the shift key on your keyboard as you click each dimension line, or you can select the manual dimension tool, and then while holding shift on your keyboard, left click and drag a selection marquee across your plan to select only dimension objects you cover with the selection marquee.”