v2.43 The occurrence of unintended black drawing

[satopian]

Thanks for the great app.
However, unintended black drawing occurs in v.2.43.
This happens with customized brushes that were fine in v.2.42.
Attach a gif animation file showing how the problem occurred.
OS is Windows10.
This problem probably does not occur if the GPU in the brush settings is off.
I attached the brush for the report with zip. Only one brush.