I'm guessing that you're creating these hyperlinks by clicking and dragging a rectangle around the link area? Unfortunately this method does not carry over to the PDF in an accessible way. Instead of drawing a rectangle, select the text that you want to become the link using the Selection tool. Now right click on the selected text and choose Create Link. You'll get the same exact dialog box, but it will now be accessible and pass the checker in Acrobat. If you look at the tag for the object, you'll notice an actual link tag and an OBJR object within.
No, I am not drawing rectangles around the link area. I select the text I want to be the link and from the type menu select hyperlink/new. From that dialog box I choose link to page and then choose the document and page within that document.
Note: I do not get an annotation error if I choose a page from within the same InDesign document or from a web URL or an email. the annotation error only appears if I chose a page in a different InDesign document (chapter) within the same book.
For example, if I create a book with a forward that includes a table of contents and ten chapters with the forward and chapters each an independent InDesign document then manually create a TOC in the forward by creating hyperlinks using the chapters name in the TOC and linking to page 1 of that chapter's InDesign document I will get annotation errors for the TOC. the links will work fine but I'll get a 508 error.
Here is a link to an example document: https://www.gipsa.usda.gov/fgis/handbook/hopHB/hopHB.html
If you download and run the accessibility checker you will find a Page Content error for 10 Tagged annotations. One for each chapter in the TOC and one for each of 5 links between chapters
I've not encountered this before but I can't say that I've created a link to another document like that. What's happening is that the links aren't being generated correctly for 508 compliance. If you look at the tags for each of those links, the OBJR object is missing which is what is causing the problem. You have two options that I can see:
1. Instead of manually creating the hyperlinks, use the actual TOC feature in InDesign to generate the TOC of those chapter intro pages. I'm sure the style on the top of each of those pages is unique so you can create the TOC in InDesign automatically. That will make the links 508 compliant.
2. Fix in Acrobat. Delete the existing links using the link tool, then highlight the text using the selection tool, right-click and choose create link. Point it to the appropriate page, and click OK. These links will be complaint and will not generate the error.
By the way, did you notice that your file is 10.67" x 14.22" in size?
Yes, we have started optimizing all of our handbooks for digital consumption (768 x1024 pixels) using mobile devices such as tablets and phablets rather than optimizing them for print. The margins are also smaller than you would see on a printed document and the font size larger (16pt) to facilitate reading on smaller devices.
Those who still want a printed copy can do that by using a 65% scaling factor in their print dialog but we are encouraging all of our users to go paperless.
1. I use the TOC feature within documents but I'm no aware of a way to create a auto TOC across two source documents.
2. I really thought this option would solve my problem but strangely it does not. I created a version of one of my InDesign Books without any cross document links then used Acrobat Pro to create the links and got the same exact error on the resulting pdf. Exploring further I discovered that even though the individual chapters of the InDesign book have been combined into a single pdf I can't create a link that crosses from one chapter to another without getting an annotation error. I can successfully create links in acrobat within a chapter without any issue. Its as if Acrobat Pro can recognize the chapters as having come from separate source documents and does not create properly annotated hyperlinks.
Out of curiosity I used Acrobat Pro to combine two PDF source documents into a single PDF and got the same result. You can't create a compliant hyperlink that crosses the boundary between the two source documents.
I'm starting the think that "the only way to win is not to play."
BTW: How do you look at the tags for the hyperlinks to see what's wrong? Is there a tool in acrobat that you use?
The tags Navigation pane is where you can see the actual tags in the document. View > Show Hide > Navigation Panes > Tags.
InDesign can create a TOC that references all of the documents in a book. In the TOC setup in InDesign, enable the "Include Book Documents" checkbox.
That being said, Acrobat doesn't know any information about what "used to be" a separate document. I've never encountered what you are experiencing which piques my curiosity. I'll try to test that.
You probably have the answer by now, but for those of you who come across this discussion for help, as I did, link to text anchors instead of pages. That's what worked for us.
I have not encounter any error which you've provided the file.