Unstable Speed with Speed Sensor connected

Yep, as a matter of fact, I noticed that as well. Just on the last ride, I was thinking, am I imagining things, or is speed really fluctuating lately like crazy?
Could be a 5.0 thing,

Check the magnet placing if there is one. Check the sensor is paired - might be an idea to remove it and re-pair it. Check the speed is coming from the sensor.

I know I have seen posts about chains becoming magnetized and interfering with sensors on back wheel. If it is on your rear wheel you might want to try moving sensor to front hub.

I know I have seen posts about chains becoming magnetized and interfering with sensors on back wheel. If it is on your rear wheel you might want to try moving sensor to front hub.

Great advise! I recently bought a STAC zero and it happened on time that the chain got catched by the very strong magnets that thing uses to create resistance. That must be the reason. Can't wait to verify!

I have seen this once or twice since 5.0. And it only lasted for 10-20 seconds or so each time, that I noticed. I was going 17mph and the speed would go down to 6-8mph. I have my speed sensor around my front hub. It is the garmin no magnet sensor. I never had any issues before 5.0. It may have just been a fluke. 5.0 has been relatively pretty good for me so far.

Great. I use the magnetless sensors on all my bikes but haven't been able to ride for 3 weeks. Most likely a band-aid used to improve ble performance, since the chipset obviously can't handle everything it's meant to handle at the same time.

I think aweatherall said that the speed sensor works by sensing the earth's magnetic field. So it is a magnetic sensor, it just does not require a separate magnetic.

One other thing to consider is that on my rides there are several places where transmission lines cause interference with my sensors. Happened in those spots with my old Polar stuff and happens with the Garmin stuff. It is much better with the Garmin stuff than with the Polar stuff. For folks with the sensor issue, is it random or does it occur regularly at the same location?

See FAQ on how it works.

https://support.garmin.com/en-GB/?faq=9NL91YJSJd3Tnyif9jRSy6&searchType=noProduct&utm_source=faqSearch

I think aweatherall said that the speed sensor works by sensing the earth's magnetic field. So it is a magnetic sensor, it just does not require a separate magnetic.

One other thing to consider is that on my rides there are several places where transmission lines cause interference with my sensors. Happened in those spots with my old Polar stuff and happens with the Garmin stuff. It is much better with the Garmin stuff than with the Polar stuff. For folks with the sensor issue, is it random or does it occur regularly at the same location?

Mine was actually associated with a certain location on a rail trail out in the middle of the woods. When I do an out and back through that location it seemed to mess up near the same spot both ways. I assumed that there was some interference.

Have definitely seen the same thing, but occasionally happened before 5.0. It is not the same place on a ride. Cruising along at 18mph....and then look down and see it at 9mph, 10mph, 9mph...and the jump back to 18mph after 5-10 seconds.
I have also noticed that autostop kicks in early at say 8mph as I come up to a stop sign (preset @ 4.5mph) and sometimes will not auto-re-start....noticed more likely to happen when not pedalling/coasting before the stop. Garmin magless speed sensor, and crank cadence sensor.

I may try moving the sensor to the front wheel (and changing the battery when I move it)...but for sure some weirdness that seems to be getting worse