Trying to Move Blocks: They Disappear

Returning to building WordPress sites after some years of not doing that. Bought GeneratePress and GenerateBlocks Pro.

I had started a Page using regular WordPress Blocks. Now I’m trying to convert to GBP blocks.

Previously, when I wanted to move something, I selected it in the Navigator side-panel, and dragged it where I want it.

When I try that now, the minute I start to drag, the items “disappear.” An icon appears instead where my mouse was on the item(s), and I can’t drag anything anywhere. The items disappear from the Page, as well. Then I have no choice but to exit the Page without saving anything. (See screen shot below.)

Each time I return to try again, the same thing happens.

I am using the nightly builds of WordPress. So I am on 6.1-alpha-53455 as I write this.

Here is the screen shot of what I’m seeing after I try to drag a headline. And it can’t be dropped anywhere. I made the screen shot wide enough so you can see the blank area where the headline used to be.

Annnnndddd…this morning it is working again.