SR is no longer the basis of RC. Its now more bounded to written rules on each difficulty specific.
if your "H-icon-normal" fits the general rules written in the difficulty specific RC of Normal diff, then its fine
However, this is not applicable to Osu!mania as it is doesnt have their specific RC just yet. Normal should be below 2* as always
if you're wondering about "insane as lowest diff" thing, read below:
If the drain time of the highest difficulty is...
...lower than 3:30, the lowest difficulty of each included game mode cannot be harder than a Normal. Because osu!mania does not have a difficulty-specific Ranking Criteria yet, an osu!mania beatmapset's Normal difficulty is defined as a difficulty below 2.00 stars. For hybrid beatmapsets that include osu! difficulties, the additional modes’ lowest difficulties cannot be harder than a Hard.
...between 3:30 and 4:15, the lowest difficulty of each included game mode cannot be harder than a Hard.
...between 4:15 and 5:00, the lowest difficulty of each included game mode cannot be harder than an Insane.
...anything higher, the beatmapset is exempt from reasonable spread rules.
if you find an insane as their lowest diffs, they are likely in around 4:15 - 5:00 of drain time.
its all in RC. have a time to re-read those because these changes is just as recent as 3 months ago