When I'm in Navigation, clicking on whichever node is in the top left-hand edge of the planet is unclickable. For example, clicking on Strata Relay does nothing. If I click and drag down and to the right, I can then click on Strata Relay.
I haven't tested this on every planet, but it is consistent on the planets I have checked.
The problem started a couple of weeks ago, maybe longer. Before that, it didn't happen. I'm on a PC, no recent changes in hardware or settings (unless Microsoft's been making "improvements" behind my back).