'Missing Data' error during sync

[jencastrodoesstuff]

After unsucsesfull attept to sync different devices with MD

Describe the bug
Error Messages after sync but data appears to have transferred.

Can you do the same thing twice?
difficult to repeat the sequence of events

1. After unsuccessful attempt to sync different devices with MD...
   S10 - Mm v2.1.0-RC.781-QA
   

S8 - Mm v5.0.0 beta 1

2. Check observation list for synced data
   S10 - Mm v2.1.0-RC.781-QA
   
   S8 - Mm v5.0.0 beta 1
   

3. Create new observation
   S10 - Mm v2.1.0-RC.781-QA
   

S8 - Mm v5.0.0 beta 1

4. Return to sync screens and hit sync
   S10 - Mm v2.1.0-RC.781-QA
   

S8 - Mm v5.0.0 beta 1

5. and watch progress
   S10 - Mm v2.1.0-RC.781-QA
   

S8 - Mm v5.0.0 beta 1

6. See error in v5
   S10 - Mm v2.1.0-RC.781-QA
   No error but no confirmation
   

S8 - Mm v5.0.0 beta 1

7. Check synced data - it appears to have worked
   S10 - Mm v2.1.0-RC.781-QA
   

S8 - Mm v5.0.0 beta 1

Expected behavior
A confirmation that sync completed successfully

[okdistribute]

This will be fixed in the next version, got a bandaid fix here
(digidem/mapeo-core#97) and @noffle is working on another approach

[hackergrrl]

@noffle is working on another approach

fyi for v9, not v8

[okdistribute]

This should be fixed in latest v5 RC, please re-open if you continue to see this issue when there is definitely no data missing :)

[jencastrodoesstuff]

Reopening this as the error message issue. Since doe appear to be happening for with both Mm and Md but the error messages are still appearing.
Here are side by side simultaneous videos

VIDEO: S8 (start 3 seconds after s10 video)

VIDEO: S10

[okdistribute]

Seems like this could actually be a case of missing data, what is the desired behavior in that case? (before, the sync would never end.. but that isn't right.)

[jencastrodoesstuff]

VIDEO S10 syncing with Desktop after some edits to observations

[jencastrodoesstuff]

Desired behaviour is identifying the observation that has missing data... at some point, if a device ID/name were included then it may become possible to find the observation source to solve the problem or optionally delete the incomplete data.... info about how to resolve the issue is generally the best solution.

Aliya's input would be valuable here.