I know text and annotations in general are getting some active work, so much of this may be known or expected at this point, but I am experiencing what I would consider unexpected behavior when overriding text.
So, if I start a file which has one dimension style in it:
1. Use the Text command and place a piece of text
2. Copy that text, then double click to modify it, such as changing it’s height.
3. Now copy that modifed text, then double click it to modify
At this point you will be asked if you want to delete current annotation style. This is the first unexpected thing. It seems Rhino is creating invisible annotation styles to store my overrides, so I’m being asked if I want to delete the invisible style created to handle the override, but I find this to be confusing.
4. Say “No” do deleting the annotation style.
5. Change the height again to somethinig unique
At this point you should see both the second copy (the one you are currently editing), and the first copy (the one you are not editing) update their size to the new unique value. This in my oppinion is a bug. I as a user am only expecting the text I have double clicked to edt to be the text that is updating. Further, there is no way for me the user to know what text is currently assigned this invisible annotation sytle, so if I am editing text in a file, there is no way as far as I am aware to know what text will be updated.
6. If you are still in the text editing window, hit OK, and now call the Text command again to place another piece of text.
Over here, the text height of the new text will be the unique value you used in step 5 rather than the text height of the expected current annotation style text height. When checking the current style, over here after saying “No” to deleting the current annotaion style, no style will be selected, which is also unexpected.
7. Now double click one of the modified pieces of text. You should be asked again if you want to delete the current annotation style. Say “Yes”.
Over here, no text editing window comes up, and all the modified copies revert back to the pre-existing annotation style that the file opened with. I find this also unexpected.
8. Now select one of the copied, modified pieces of text. In the properties window, notice that both the Style and Height is (varied). Select the height text, and start to type a value.
Over here this crashes Rhino (I sent in the crash report).
So, the TL;DR version, I find it weird that editing one piece of text can inadvertently modify another piece of text 
Thanks,
Sam