Android 11, Moto G5s+ - suddenly getting KeyStoreException: Not implemented - Android Q&A, Help & Troubleshooting

Hello,
I'm using a Moto G5s+ (sanders). For this phone, ArrowOS has been in use since Feb. 2021, and I have always been able to buy a subway ticket using the local operator's app MVG Fahrinfo[1].
This worked until at least May 15th, 2022.
In between, ArrowOs ceaded to support Android-11 (and this phone in generel), which is why I'm now updating the ArrowOS-11 code using the AOSP-Security Updates.
I know, I've updated the app in May or June, but I haven't used until June 3rd, when I noticed, that the MVG Fahrinfo crashes completely when I try to buy a ticket. I don't know, if or what they've changed. But moving my ArrowOS image back to a version that was definitely working did not help.
Using adb logcat, I get the following trace:
Code:
07-13 07:33:34.730 481 481 I qseecomd: type=1400 audit(0.0:2922): avc: denied { ioctl } for uid=1000 path="/dev/block/mmcblk0rpmb" dev="tmpfs" ino=2367 ioctlcmd=b300 scontext=u:r:init:s0 tcontext=u:object_r:block_device:s0 tclass=blk_file permissive=1
07-13 07:33:34.741 1974 9203 W keystore: Trying to serialize unknown tag 1879048895. Did you forget to add it to all_tags_t?
07-13 07:33:34.831 1974 1974 I keystore: del USRPKEY_a9fa3a48-b564-4a15-9810-ab0c00e54249 10209
07-13 07:33:34.831 1974 1974 I keystore: del USRCERT_a9fa3a48-b564-4a15-9810-ab0c00e54249 10209
07-13 07:33:34.832 1974 1974 I keystore: del CACERT_a9fa3a48-b564-4a15-9810-ab0c00e54249 10209
07-13 07:33:34.830 481 481 I qseecomd: type=1400 audit(0.0:2923): avc: denied { ioctl } for uid=1000 path="/dev/block/mmcblk0rpmb" dev="tmpfs" ino=2367 ioctlcmd=b300 scontext=u:r:init:s0 tcontext=u:object_r:block_device:s0 tclass=blk_file permissive=1
07-13 07:33:35.023 8070 8082 I hrinfo.muenche: Background young concurrent copying GC freed 235652(12MB) AllocSpace objects, 234(14MB) LOS objects, 45% free, 31MB/58MB, paused 181us total 104.730ms
07-13 07:33:35.064 8070 8092 D TransportRuntime.SQLiteEventStore: Storing event with priority=HIGHEST, name=FIREBASE_CRASHLYTICS_REPORT for destination cct
07-13 07:33:35.097 8070 8092 D TransportRuntime.JobInfoScheduler: Scheduling upload for context TransportContext(cct, HIGHEST, MSRodHRwczovL2NyYXNobHl0aWNzcmVwb3J0cy1wYS5nb29nbGVhcGlzLmNvbS92MS9maXJlbG9nL2xlZ2FjeS9iYXRjaGxvZ1xBSXphU3lCcnBTWVQ0RkZMMDlyZUhKaTZIOUZZZGVpU25VVE92Mk0=) with jobId=1899902110 in 1000ms(Backend next call timestamp 1657115477558). Attempt 1
--------- beginning of crash
07-13 07:33:35.113 8070 8070 E AndroidRuntime: FATAL EXCEPTION: main
07-13 07:33:35.113 8070 8070 E AndroidRuntime: Process: de.swm.mvgfahrinfo.muenchen, PID: 8070
07-13 07:33:35.113 8070 8070 E AndroidRuntime: java.security.ProviderException: Failed to generate attestation certificate chain
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.security.keystore.AndroidKeyStoreKeyPairGeneratorSpi.getAttestationChain(AndroidKeyStoreKeyPairGeneratorSpi.java:611)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.security.keystore.AndroidKeyStoreKeyPairGeneratorSpi.createCertificateChain(AndroidKeyStoreKeyPairGeneratorSpi.java:498)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.security.keystore.AndroidKeyStoreKeyPairGeneratorSpi.generateKeyPair(AndroidKeyStoreKeyPairGeneratorSpi.java:475)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at java.security.KeyPairGenerator$Delegate.generateKeyPair(KeyPairGenerator.java:727)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at b.b(Unknown Source:28)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at c$a.invokeSuspend(SourceFile:6)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(SourceFile:4)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at kotlinx.coroutines.DispatchedTask.run(SourceFile:22)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:938)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.os.Looper.loop(Looper.java:223)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:7665)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:594)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: Caused by: android.security.KeyStoreException: Not implemented
07-13 07:33:35.113 8070 8070 E AndroidRuntime: at android.security.KeyStore.getKeyStoreException(KeyStore.java:1306)
07-13 07:33:35.113 8070 8070 E AndroidRuntime: ... 15 more
07-13 07:33:35.116 2534 9249 I DropBoxManagerService: add tag=data_app_crash isTagEnabled=true flags=0x2
07-13 07:33:35.117 2534 6885 W ActivityTaskManager: Force finishing activity de.swm.mvgfahrinfo.muenchen/.mobilityticketing.MobilityTicketingActivity
Therefore, it seems to me, that either
the app has changed and now requests something, that it did not before: but then, why does not work now?
my ArrowOs image (one I created myself, adding AOSP's security updates) changed/deleted something, that does not get restored switching to another image
something else?
Can you help me out? Please do not hesitate to ask, if you need anything else to debug.
Thanks a lot in advance.
kniffte
1: https://play.google.com/store/apps/details?id=de.swm.mvgfahrinfo.muenchen&hl=de&gl=US