AFAIK there used to be (still is?) a bug where the Hotspot visuals just didn't show up anymore on a case-by-case basis.
I had two cases in the past :
- visuals didn't show but Hotspots were still in the NAV Panel when close enough (a few Ls max. , sometimes closer than that)
- neither scanned hotspots nor Visuals appeared, required DSS re-mapping of Rings
I'm not 100% sure but I recall that used to happen most predominantly with Rings where only the Rings were scanned - but not their Bodies (Planet/Gas Giant).
I never found out if selling UC Data for that System fixed that, but at some point it looked like that might have been the key.
(i.e. Scan & Mine, forget to sell UC Data or it being <20LY limit - the return to find the Hotspots gone and having to re-scan them with the DSS)
But for as long as a DSS is fitted, any scanned Rings >should< display properly. Should.