Cannot tab consistently between content controls after Restrict Editing is enabled

[bdramsey]

(Note: I'm using desktop Office 365, which I believe is an alternative form of Office 2016, it's been behaving identical to 2016 as far as I can see.)

I have an account form I've thrown together in Word, using tables for formatting with Plain Text and Checkbox content controls inside some of the cells. For ease of use, being able to Tab between the controls is really important for the users, but for some reason when I enable Restrict Editing it goes from behaving exactly as expected to... really weird. It will inexplicably skip over certain controls, and get stuck with the message "You can't make this change because the selection is locked." at the bottom status bar.


Here are some screenshots of what's happening. First, how it behaves normally before restriction is enabled: [no screenshot]

It tabs from left to right and row by row, exactly as expected. Now here's what it does with restriction enabled: [no screenshot]

It starts off fine, tabbing between the Plain Text controls just as before But then it skips over the "New Account" checkbox, goes to the next one over, then becomes stuck. Here is how I'm restricting editing: [no screenshot]

Any ideas why this is happening or how to stop it? I examined the Properties using the Developer tab, and all of them seem nondescript, i.e. the first checkbox is identical to the second one, as well as the third. I even tried moving the checkbox controls into their own table cells since right now they're directly next to the text part, but that did absolutely nothing.


EDIT: Google drive killed all the images that were just working a few minutes ago when I posted it. Just use your imagination I guess.