With the batteries out, you might try shorting the + and - terminals together.
That should neutralize any charges in the radio that the batteries might "see."

I first learned of the problem when I changed batteries in a watch. The
instructions gave the wrong places to short out but I figured out what they
wanted to do.

When It happened on my DX-392, I knew what to do as well as when my batteries
quit in my eTR7 while it was operating.

Bill, K5BY