With regard to this issue, I have good news and bad news and good news. The first good news is that it is fixed in our development builds (which will eventually be Revit 2018). The bad news is that in spite of the fact that we worked really hard to get a fix that we can put into R2017 SP2, we discovered that all possible service pack remedies are simply too risky and would likely generate worse problems (e.g. crashes).
But the second good news is that, for those of you who really need to put text into these annotation symbols in R2017, you can achieve the same results by using a label in a generic annotation. It's not overly complicated, and it would only need to be done for the five problem annotation families (Section Heads, Section Tails, Grids, Spot Elevations, and Level Heads).
Here's how you'd do it for, say, Section Head - Filled:
1. In your project's Project Browser find Families > Annotation Symbols > Section Head - Filled. Right-click on it and choose Edit.
2. Open a Generic Annotation template (New > Family > Annotations > Generic Annotation.rft) and open a new generic annotation.
3. In the generic annotation, place a label and edit it.
4. For the label, create and add a new text instance parameter. Make sure it has the text size that you want (change by selecting the label and clicking Edit Type).
5. Click Load into Project and choose the Section Head - Filled family. Click to place the generic annotation where you want it to be. Click on the "?" of the label and type the text you want the section head to display in the model.
6. Click Load into Project and choose the project. Choose to overwrite parameters and values. OK
7. The label text will now show up just like regular text would have, but the label text will remain visible even after saving, closing, and re-opening the file (unlike regular text in R2017).
We apologize for not being able to fix this in a safe way in R2017, and we hope that this workaround will help out those who still need to have non-disappearing text in these annotations.
Thanks,
Trey
TreyKlein
Principal Revit QA Analyst