AstroPad closes and Photoshop becomes unresponsive

I use AP with an iPad Pro 12” 2nd gen and a MacBook Pro 15” (mid 2015) with 16 GB of RAM. I’M USING AstroPad Standard and the latest Photoshop CC. I only use USB connection.

I can be working along fine, saving frequently and the AstroPad window collapses top and bottom and Photoshop becomes unresponsive on my MacBook. I have to move the cursor off the Photoshop window to click on my desktop, the click back to the Photoshop window before I can save. Often I hear a “ping” of my iPad reconnecting. Sometimes the iPad will “ping” repeatedly, indicating some connectivity issue. If I switch the USB cord to the other port on the MacBook, it sometimes resolves.

What’s going on?