contact count and matching keys doesn't match, 5 contacts

[patrick-werner]

The CWA shows a red status and 5 contacts -> high risk.
The logs are showing matchcount: 1. This means i had 5 contacts with a single person on one day? I'm asking because on the day in question i didn't had contact with anyone i don't know (also know their green app status). So i'm assuming receiving beacon signals from one of my neighbours through the wall/ceiling.

Attached Screenshot and Log from the CWA App (iOS 14.1 und CWA 1.5.1).

[daimpi]

@patrick-werner thanks for posting this… Just to mirror some information from over at the community Slack:

There is only one check which shows one match in the log entries for today:

 {
          "Hash" : "4CF0C497455611780A6E99FE12B16AC70DD135BB6D2769AFB0FB10A56F425722",
          "MatchCount" : 1,
          "KeyCount" : 14309,
          "AppBundleIdentifier" : "de.rki.coronawarnapp",
          "Timestamp" : "2020-10-24 17:13:04 +0200"
        }

This usually would mean 1 encounter/exposure in CWA, but not in this case for some reason 😕.

Here are all the log entries for today in a table:

Details

Timestamp	Hash	MatchCount	KeyCount	Timestamp.1
24.10.2020 17:12	064B723E5EDD2EB8CD4C36FAA67FE839A486451748A5521B447606795867A061	0	18645	24.10.2020 17:13
24.10.2020 17:12	D6C9ADEF176488BB7BCFA9F3A01EB5A9F692817441B777A630A1F74131A03CDF	0	16122	24.10.2020 17:13
24.10.2020 17:12	4CF0C497455611780A6E99FE12B16AC70DD135BB6D2769AFB0FB10A56F425722	1	14309	24.10.2020 17:13
24.10.2020 17:12	D63C8A25912DA34CD9A266967B854BB98BC09290BFE12B804C1FD796AE64BBD3	0	10876	24.10.2020 17:13
24.10.2020 17:12	F049E50F243C7B991867B229668A44CBCA6E63846EBECA0A2B8E3C0BA8B7ACAC	0	6386	24.10.2020 17:13
24.10.2020 17:12	3908E8EF3DE421C31CD585B8CBAFCEA7D54C21BF94E5E690A477AEE217E8B95A	0	4814	24.10.2020 17:13
24.10.2020 17:12	F9073A1268C72E6C93884F761E27066E9455BCFC0EFDB5068EA8C0BAAF1E098E	0	16674	24.10.2020 17:12
24.10.2020 17:12	41444FD9FFAEFDD39A78B11E59DD58EF2146D5F65D39E7607C0E1997712B737F	0	43934	24.10.2020 17:12
24.10.2020 17:12	1A7FA72A1A077EBD7EC11F0F8B3BB482A22865B133E9B45D66EA7AF11D5AAC53	0	41646	24.10.2020 17:12
24.10.2020 17:12	8F2EA05416F4175417980FFEC401506135A9591AC6A6F715CB94BF6A92723AA4	0	34105	24.10.2020 17:12
24.10.2020 17:12	DB52431B890F3BC23B5C1BF902CC6EB2EDE0ABD827ABD58C207CA20E525B1008	0	28218	24.10.2020 17:12
24.10.2020 17:12	35FC7AAA7F90C04599FE355EA2AFEDC18A93F74E2AFB8E152C138EF0704E171C	0	18134	24.10.2020 17:12
24.10.2020 17:12	9CCB79003AEC7BAAAA5F2733453AF4DAE414919FECF388344F8C4F7F21C47581	0	14649	24.10.2020 17:12
24.10.2020 17:12	970614A4D5AED5E567649FC508C6013847B446E03881A69647986950B497F227	0	23657	24.10.2020 17:12
24.10.2020 14:58

There seemingly was an attempt to perform checks at 14:58 (but the entry is empty, so seemingly it didn't work) and then the actual checks were performed at 17:12 which is also the timestamp which shows up in CWA… but even there, only one match in one of the packages is found 😕.

[daimpi]

One question @Ein-Tim @ndegendogo: you also have encounters/exposures under iOS 14.1 and CWA 1.5.1, right? Is your EN log showing the same number of matches as your CWA?

[ndegendogo]

Is your EN log showing the same number of matches as your CWA?

@daimpi yes, always. And I am verifying this daily.
I could not check during 5 weeks with iOS 13.7 because of a bug (#1106), but before and afterwards I did never see a deviation.

cwa 1.5.1 since two days
iOS 14.1 since three days
So, no long-time experience with exactly this configuration.

[ndegendogo]

@patrick-werner your ENF log file shows a match since 3 days.
Did you check cwa the days before? Are you aware if this strange mismatch was there from the beginning (all these three days)?
If you checked cwa: was it always red, or was it green (green with encounters) before?

[ndegendogo]

One crazy (?) idea on this: could it be that Apple fixed their bug (#1106) only partially in 14.1, and still suppress some of the encounters in their ENF log file??

[ndegendogo]

@patrick-werner which iOS version exactly do you have? Is it the "official" version, or some preliminary / special version for developers?

I noticed that the "build" number in the second line of your ENF log differs from mine.
I had always taken this number as indication of iOS version.

My number is (with iOS 14.1)
"Build" : "18A8395",

Your ENF log shows:
"Build" : "18A393",

@Ein-Tim could you please check your number?

[Ein-Tim]

@daimpi yes, always. And I am verifying this daily.
I could not check during 5 weeks with iOS 13.7 because of a bug (#1106), but before and afterwards I did never see a deviation.

Can verify this, always had same amount of "matched Keys" and Encounters in CWA @daimpi

[Ein-Tim]

@Ein-Tim could you please check your number?

Yes, my Build number is 18A8395 (like the Number from you)

Your ENF log shows:
"Build" : "18A393",

This is the Build Number from iOS 14.0.1, the version which fixed #1106 is iOS 14.1 (18A8395) so I think he had 1 Red Encounter, this one got logged but he also had 4 Low Risk Encounters and these did because of #1106 not get logged...

@patrick-werner Please update to iOS 14.1

[patrick-werner]

oh wow. I was 100% sure beeing in iOS 14.1, which i wasn't. Thanks for the explanation, sorry for not being aware of my device s/w version.

Thanks @Ein-Tim & @daimpi !!!

[daimpi]

@patrick-werner no worries and thanks to @ndegendogo and @Ein-Tim for solving this riddle ❤️.

This was really very curious, as seemingly Apple went all over the place with what they showed in their log… I was under the impression that #1106 meant full suppression of all the matches, but seemingly that was only true for some versions. E.g. we had someone with red exposures on "iOS 14 public beta 8" ("Build" : "18A5373a") reporting here that they had 0 matches in their EN log with 14 (red) exposures shown in CWA. But this behavior was then seemingly changed again for iOS 14.0.1 and finally really fixed with 14.1. Fun times ^^.

Edit: Just out of curiosity and to spot similar issues earlier: is there some place where one can look up which build number corresponds to which iOS version?

[ndegendogo]

is there some place where one can look up which build number corresponds to which iOS version?

I am not aware of any "official" list of this kind.
I have only an (incomplete) private list compiled of my own version history, plus a few from users ENF logs posted here.

[ndegendogo]

Wikipedia lists them (~semi-official)