Edge 1040 (21.18) Drops All Sensors Just After Starting a Ride (when using ConnectIQ Data Fields)

An 840 Solar, to be precise.

I see. The threading in this forum sometimes is a bit hard to decipher. Anyway, I didn't even know the 1040 had LTE. Does it a have cell connection? I certainly did not activate any SIM or plan on it.

As I understand it, he sets the phone to only use LTE data connection, instead of falling back to 2g/3g (which normally is something like an Auto setting, or 2g/3g/4g/5g). He also states somewhere that he thinks the issue occurs when the phone switches back to a slower data speed (2g/3g). Which would imply that some proces on the Edge hangs or times out while waiting for data (which never comes, or comes too late). 

I don't think the problem is in de Windfield app, but more in the way ConnectIQ handles data transfer and timeouts from data transfer. Most CIQ apps don't actively use a data connection via the phone, so they won't be affected. Windfield actively needs a data connection to get up to date weather info. So it would seem kinda logical that if there's something wrong with the ConnectIQ coding, and the whole ConnectIQ runtime in the edge hangs while waiting on data that never (or very slowly) arrives, other ConnectIQ apps would be affected. 

No. I'm talking about "LTE only" mode for my Android smartphone. When my phone changes network mode between LTE and H+, between H+ and H etc. then I got sensors dropout.

"LTE only" mode makes my phone don't change network mode. So I'm not getting sensors dropouts.

During two months I tested "LTE only" and got only two or three dropouts during whole this period. And got 3-5-10 dropouts everyday before switching to "LTE only".

I have an iPhone. I don't think there is such a mode there. However I do have a spot that I ride through immediately upon setting off on a ride, where there's EDGE coverage at best. So maybe the switch from Wifi/3G at the ride's starting point to EDGE just a few seconds later does cause this. But if that is the culprit, it still is a software bug. No reason this should cause other sensors to drop out, that are on a client to client direct ANT+ connection. The data update to the Connect IQ fields via the phone should be completely independant. At worst the Garmin should just drop those fields or show something like "--" or "N/A" for them.

I agree it's a software bug. I think it's somewhere in the CIQ code that handles the http(s) connection between the Garmin via BT through the phone to the internet. It looks like the whole CIQ interpreter gets messed up at some point when the data connection is slow or fails.

having same issue, what's the fix with an Iphone?

I've got same issue on my out-of-box 1040 - all sensors like Garmin HRM, Duo, Garmin speed, Stages power meter - all disconnected, and couldn't connect back until Edge restarted. It looks like the ANT+ function of Edge failed completely, not just a specific sensor connection. 

I experienced this only ONCE and right after after adding a new ConnectIQ field  called "BatteryUpDown"to my datascreen. And before that I already had WindField only and no such issues (total disconnect of all sensors no matter which) whatsoever. 

So I thought maybe this BatteryUpDown IQ field was guilty, and removed it, keeping old good WindField with which I never had any issues. And now it's all back to normal, or at least seems so for several other rides.

that's some good validation that it's not windfield.  it's just some a nasty ConnectIQ bug that garmin hasn't been able to figure out