I am a new user of AD on an iMac 27" running Catalina 10.15.1 and having the same issue. Dragging a guide onto the canvas does not show up. It does however show up on the rulers. The document is an SVG export from Gravit. No amount of fussing with the Document Setup or Guides Manager was able to 'trick' AD into making the guides appear on the canvas.
I did create a new document in another tab with the same dimensions and the guides I dragged onto the canvas were there. From here I tried to get the guides to 'disappear' hoping to discover a setting combination that might be causing the issue, but no luck.
Hopefully someone will be able to hunt down the bug. For now I'm copying imported SVGs into new docs.
