/e/ OS location service jumps between correct and fixed wrong location

I have /e/ OS 1.18 installed on my phone. Ever since I've started using /e/ OS, occasionally my phone would pick a semi-random* fixed location and then alternatingly pass on either my real location or the randomly picked one to apps using the location service. *By semi-random I mean that it is usually relatively close to me (generally no further than 100km) and usually in a plausible place (a public road, square, railway station...) but otherwise wholly inexplicable. In the past I had some luck with clearing cache & storage of the System App called Nominatim Geolocator (or similar) – this would fix the problem for a few weeks – but in my current version of /e/ OS I cannot find this app anymore. In the Advanced Privacy settings, I chose to expose my location and IP address, but this did not help. Neither did clearing cache & storage of Advanced Privacy, nor disabling Advanced Privacy as the mock location app via the developer options. What can I do to permanently get rid of this problem?