After launching desktop Firefox, the first time, the returned position is at 300 km of my real position

[SuperPat45]

After launching desktop Firefox, the very first time I click, the returned position is at 300 km of my real position, with an indicated accuracy slightly higher than 8000 m.
The second time I click, on second later, it works fine.

Maybe you should check again in this case.

And you should never return a position with an accuracy > 8000 m

[domoritz]

I cannot reproduce this issue from the description and this seems like a problem with leaflet itself, no?