I'm experiencing this issue within Photoshop CC 2018/2019:
1/ I create guides around smart object.
2/ When setting up Perspective Warp grid, I position perspective grid corners at the smart object corners with the help of snap to guides.
The result is Program Error and even the Perspective Warp hes been applied, I cannot do anything and even cannot save the file because of program error message. I have to delete smart object to be able to save the file and continue to work.