I totally agree with Mike’s comments about being in the correct lane to safely complete your navigation of the roundabouts.
If I can throw another Cornish double roundabout into the mix this seems to have even more issues than the examples you gave. The roundabouts are in St Austell and are on the main route to The Lost Gardens of Heligan (via Pentewan Road B3273) so will be used by many people unfamiliar with the area. Coordinates are 50.3345578280603,-4.793913523573934
I assume from looking at Edit that HERE consider a roundabout to be multiple sections of road linked together rather than a single physical entity?
Trevanion Road A390 approaching the roundabout becomes 3 lanes from a single lane. Going away from the roundabout it is 1 lane but shown as 2-3 lanes on HERE. I assume that in Edit the road would need to be split to show the correct number of lanes in each direction?
The roundabout that Trevanion Road enters is shown as 1 lane on HERE – how can a 2-3 lane road become a 1 lane road? The road should become a 1 lane road before the junction? Surely, HERE’s basic system validation should at least raise this as a concern if not prevent it from happening?
Pentewan Road and South Street also become 3 lanes when joining their respective roundabouts with 1 lane leaving the roundabout but are shown as 1 lane in each direction on HERE. Penwinnick Road becomes 2 lanes when joining the roundabout with 1 lane leaving the roundabout but is shown as 2-3 lanes in each direction. The sections of road that make up both roundabouts are all shown as single carriageway road. The section of the A390 linking the 2 roundabouts is correctly split and shown as 2-3 lanes in each direction.
Does HERE have any plans to allow different numbers of lanes on opposite sides of a single section of road as with different speed limits? The exact number of lanes would need to be specified with a facility to link lanes to the destination road (and lane?) as Mike has done in his examples with the coloured lines.