Have you run the Adobe Accessibility Wizard?
I just experienced the weirdest thing, in that I walked away from those two IRS forms right after posting that last message, just fired up NVDA again (I'd never closed the Reader DC instance where the forms are displayed) and I can now, for no explicable reason, navigate the accessible version (didn't try the other) with TAB and shift tab, focus is being clearly indicated visually as well as NVDA announcing the thing I've landed on, checkboxes are checking/unchecking using the spacebar to change the state, and it's otherwise behaving exactly as I would have expected from the outset. Even the auto-switching between browse and focus mode is doing what it should
I cannot account for the cause of this change in behavior, other than to say I had started NVDA prior to opening the first IRS fillable PDF, then Adobe Reader DC which detected I had the screen reader on and asked if I wanted to run the accessibility wizard (which I did), and when it appeared the wizard was done starting to play with the form, which at that time was misbehaving badly.
Now it's not misbehaving badly and is, in fact, behaving exactly the way I would have predicted. I had shut down NVDA before going out for a short walk, so maybe if the accessility wizard is run for the first time with the screen reader already active whatever it is that the accessibility wizard configures for the screen reader is not visible to the screen reader until it has been restarted.
Brian - Windows 10, 64-Bit, Version 21H2, Build 19044
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