Calls on other devices is inconsistent (iPhone X)

I have my iPhone X “Calls on other devices” activated for my iPad Pro 12.9 (5th gen). It previously worked, before I revised the OS to iPadOS 15.3.1. Or maybe it was the same upgrade on the iPhone that caused the problem. The iPad Pro receives texts intermittently and phone calls not at all. Both texts and calls were successful until recently.

In addition, the iPhone X shows two iPad Pro 12.9 devices. I only own one. There’s no way to identify the specific iPad Pro 12.9 device in the “Calls on other devices” setting on the iPhone.