I am also having this issue but in my circumstance it is all meraki equipment, and it has been connected for a while with no change.
Ive just submitted a case to see if there is something that can be done to have a forced update.
All my MR switches connect directly to an MX but our topology is reflecting that some of our switches are conected via switches instead of directly to our MX.
This is a little frustrating as it introduces doubt into me with regards to the rest of the information that is being displayed.
I am not feeling 100% confident everything that is show is accurate.
Would be good to get this fixed.