In article .com,
"Kingfish" wrote:

Lockheed P-38 Lightning revealed Mach tuck phenomenum, its cause and
fix.

It wasn't mach tuck IIRC as the plane wouldn't go that fast. It was
flight control compressibility in a high speed dive that froze the
stick. The J model had dive brakes for just that reason.

I stand corrected. It was indeed compressibility. Thank you!