Problem Using Adjustment Brush

When editing photos using the adjustment brush, after adding numerous brush strokes Lr starts to slow down significantly.  Then while making edits to brush strokes or adding new brush strokes the Lr screen suddenly goes black for a couple of seconds up to 10 or more seconds.  The only thing showing is an hourglass.  When the image screen reappears, there is frequently an erratic straight-line brush stroke across the screen.  The erratic stroke frequently goes completely off the edge of the image and returns in a “V” shape. When the screen goes black there is a notation at the top left side of the screen in the title bar to the right of Adobe Photoshop Lightroom Classic – “(Develop Not Responding)” or “Lightroom Classic (Not Responding)” .   Is that a Lr Classic bug or is there something else going on?  I have tried deleting the History and it appears to help the response slightly, but it does not eliminate the erratic brush strokes or the black screen.  

I attached 2 files as examples.

System Information:

Win 10;  Lightroom Classic version: 9.4;

Processor: AMD Ryzen 7 3700X 8-Core 3.6 GHz;   

Graphic Card: AMD Radeon RX 5700 XT

Memory: 32MB;  Monitor: ViewSonic VP2768-4K

Any help would be appreciated.

Thank you