I think this is a bug specific to the UIAButton element - possibly specific to buttons in UIATableView - because “value” can be retrieved from other elements (i.e. UIAStaticText) without issue. I also saw another thread where someone else experienced the same issue, and it doesn’t appear that a resolution was found.
Here’s a link to the issue as reported about one year ago. In this thread I made an attempt to escalate this issue, or at least confirm whether or not it is a bug: iOS App UIAButton unable to get name with get_attribute('name')