I just discovered that renaming a repeating section on a form is not something that you should do if you already have items submitted into a list. Below is what the repeating section looked like originally.
And this is what was displayed after I changed the name of the repeating section and re-published.
The fix is to change the repeating section back to its original name. After doing that, the contents displayed correctly once again. So, if you (or someone else on your team) renames a repeating section, please be sure to capture its original name before you publish the change.