Discrepancy between planner ETA and navigation ETA

🚧 THIS IS A TICKET MIGRATED FROM UPVOTY. The original ticket and comments will be available for a limited time over at:
https://abrp.upvoty.com/b/report-a-bug/wrong-eta-and-wrong-battery-estimation/
———————————————————————————
"See screenshots:
Navigation displays unrealistically optimistic ETA and battery remaining values (screenshot 1) Despite the planner showing correct values (screenshot 2). Once the ETA reaches zero it becomes negative.

This bug is reproductible every time I take this route (A51 highway from sisteron to la saulce, in france). It looks like navigation somehow ignores a portion of the route.

It only happens one way (northbound), so something must be wrong with the map data on that section. I looked around on the openstreetmap editor to try and find missing metadata but it looked fine."