White flickering/boxes when Dragging n Dropping

[Jeff-Clark-MST]

• I'm submitting a ...
  [x ] bug report

• What is the current behavior?
  sometimes when dragging/dropping my page shows white flickering and/or white boxes either behind or near the drop item. These white backgrounds/boxes are random in size, sometimes small, sometimes half the size of the page. These also appear in a random z-index order. always behind the droppable element but sometimes on top of or behind other elements on the page.

• If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://plnkr.co or similar.
  I have a 3 column layout, with html, body and each column set to 100% height with overflow-y: scroll. if i change the size of the window, by resizing it on the fly the white boxes disappear until i start again. Im dragging text from a list onto an text input

• What is the expected behavior?
  No white background/boxes should appear on the page

• Please tell us about your environment:

• Angular version: 5.0.3
• Angular CLI Version: 1.6.5
• Browser: 63.0.3239.132 (only tested in chrome)