The objects were far away from drawing's origin 0,0. Such distance values may cause glitches.
I've moved them back to 0,0 and switched the viewport's Shade plot value from As Displayed to Hidden.
See the final result capture below and attached fixed file.
![Screenshot 2021-05-27 200440.jpg Screenshot 2021-05-27 200440.jpg](https://forums.autodesk.com/t5/image/serverpage/image-id/923960i2F549B35D482129E/image-size/large?v=v2&px=999)