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CGM data not appearing after Pod change; Loop stops Looping #2278
Description
Describe the bug
Since I have updated phone from iPhone 8 to iPhone 12 Mini, including migrating to iOS18 we have had the following behavior at a pod change:
-
Loop receives Dexcom CGM data in the CGM details tab, but does not make it to the BG data in the Loop main screen so closed Loop goes stale
-
Loop pump shows "Signal Issue" even if there is a correct connection to pod, manual bolus can be done and pod status log accessible
current fix for the above 2 problems is to "kill" both Loop and Dexcom apps, reopen, insert manual BG into Loop, wait 5 minutes and it all comes somewhat back to normal
- Afterwards for about 8 hours the predicted BG does not appear on Nightscout nor on LoopCaregiver app. Magically after this waiting period the predicted BG reappears everywhere.
Attach an Issue Report
I will get this on the next pod change
To Reproduce
In our case, change pod
Expected behavior
No interruption of BG and reconnection to new pod seamlessly
Screenshots
Will get these on next pod change
Phone
- Hardware: iPhone 12 Mini
- OS Version: iOS 18.2
Loop Version
- Version Number: 3.4.4
- Repo: Loopkit/loopworkspace.main
CGM
- Device: Dexcom G7
- Manager app: Dexcom G7 iOS app
Pump
- Manufacturer: Omnipod
- Model: DASH
- Firmware version: n/a
Additional context
Add any other context about the problem here.
Activity
Ericcarbonn commentedon Jan 22, 2025
Here is the Loop issue export and some pictures from a couple days ago after pod change. Pictures show Loop app CGM receives BG values but they do not show up on Loop main screen, and are not taken into account. It also show the signal loss issue that is present at the same time.
I force closed Loop, Dexcom. Restarted both apps. Entered current BG manually from value in Dexcom app. After everything came back to normal. In this case I did the fix within minutes after the pod was changed.
Loop Report 2025-01-15 02_36_37-05_00.zip
marionbarker commentedon Mar 14, 2025
There is an open PR to G7SensorKit that is improving G7 connectivity as long as the Sensor is communicating with the app. It is not perfect and some people are still having trouble.
Please see: LoopKit/G7SensorKit#33
This can be added to released version of Loop (see G7 Missing Readings option) using a the Customization Select Script:
[-]CGM data not appearing after Pod change[/-][+]G7 CGM data not appearing in Loop when available in Dexcom G7 app[/+]marionbarker commentedon Mar 19, 2025
This is the second official report of the G7 CGM missed readings in Loop. This is also seen in Trio and iAPS. This has nothing to do with the pod change, so I edited the name.
This is a real Issue and is under investigation.
Closing this Issue and keeping #2265 open.
Ericcarbonn commentedon Mar 19, 2025
marionbarker commentedon Mar 19, 2025
Thanks for the clarification.
There must be something strange going on with Bluetooth on your phone to affect both the Pod and the G7SensorKit.
Can you try adding this customization? (We don't know if this is a "fix" but it seems to help some people who are just having the G7 sensor problem).
I see you have a LoopReport posted. I'll go an look at that in detail.
marionbarker commentedon Mar 19, 2025
I looked at your report. There is no gap in communications with the pod when you put a new pod on. I see communication between Loop and the pod every 3 minutes as expected. The act of changing the pod must be disturbing your G7 interactions, so you are not getting updated glucose. With no glucose coming in, the Loop app goes red.
@ps2 Is there a test you would like @Ericcarbonn to run the next time he changes a pod.
marionbarker commentedon Mar 19, 2025
I am also not seeing gaps in the Dexcom "didRead" messages with the exception of one set of backfills. So I am very puzzled.
One more thought. The current OmniBLE version used by Loop 3.4.4 can have a rare state where the app thinks it is suspended when it really isn't, so it won't send an automated command. (We've only seen that in Trio, not in Loop).
Can you do the normal pod change through insertion.
Once pod is ready to go, suspend Insulin and then resume Insulin.
See if that resolves your issue.
Ericcarbonn commentedon Mar 19, 2025
Ericcarbonn commentedon Mar 20, 2025
marionbarker commentedon Mar 20, 2025
I don’t think you posted the Loop Report. There are 84 hours of messages in the Loop Report. We picked that number to enable us to capture the complete history of a pod.
Ericcarbonn commentedon Mar 20, 2025
marionbarker commentedon Mar 20, 2025
You are still not attaching a Loop report. Perhaps you would have better luck with zulipchat. You can send me a private message there.
Also worth joining zulipchat to see Pete's instructions for installing a bluetooth logger and collecting a sysdiagnose for helping him resolve this issue.
LInk: #development > 3.5.0 Bluetooth oddities @ 💬
marionbarker commentedon Mar 20, 2025
I got the Loop report and graphics via DM on zulipchat. Adding for completeness.
There is no sign of loss of G7 signals in the log.
There is no sign of loss of pod communications in the log.
But Loop definitely stops looping immediately following the pod change.
Loop Report 2025-03-19 21_41_11-04_00.md
[-]G7 CGM data not appearing in Loop when available in Dexcom G7 app[/-][+]CGM data not appearing after Pod change; Loop stops Looping[/+]marionbarker commentedon Apr 24, 2025
Have you continued to have this problem?
If so, please build Loop 3.6.0 and let us know if it is still happening.
If I don't hear back, then I will close this issue in a week.
Ericcarbonn commentedon May 17, 2025
@marionbarker
I have built 3.6.0 and my son seems to indicate he still does the workaround. He's a 15y old teenager so it's kind of hard to get some form of cooperation. 🫣
I will try to check this out on next pod change and report back here.
marionbarker commentedon Nov 19, 2025
This error started happening to me too for the last few pod changes. I am using release 3.8.2 with some customizations.
I changed a pod this morning and have a red loop with no glucose showing from the time the pod was activated. If I tap on the
- - -for glucose, it shows me the last reading from the G7.I rebuilt with Xcode so I can capture the log. But this is the same process as a quit/restart and after I let it run for a CGM cycle, the problem cleared up and I have a green loop again.
Next pod change, I will try to remember to build to Xcode before I change the pod so I can captured a debug log and see if I can find an issue.
In case it is useful, I saved the Xcode log for the rebuild.