HEAD request from SSO-authorized client app leads to Nextcloud app crash

[0xf104a]

⚠️ Before posting ⚠️

• This is a bug, not a question or an enhancement.
• I've searched for similar issues and didn't find a duplicate.
• I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
• I agree to follow Nextcloud's Code of Conduct.

Steps to reproduce

The following code which executed in client application leads to Nextcloud app crash when called

@Override
  public boolean checkNewNotifications() throws Exception {
      NextcloudRequest request = new NextcloudRequest.Builder().setMethod("HEAD")
              .setUrl(Uri.encode("/ocs/v2.php/apps/notifications/api/v2/notifications", "/"))
              .build();
      Response response = API.performNetworkRequestV2(request);
      String lastEtag = Objects.requireNonNull(response.getPlainHeader("ETag")).getValue();
      Log.d(TAG, "lastETag=" + lastEtag);
      Log.d(TAG, "mETag=" + mETag);
      if(!lastEtag.equals(mETag)){
          Log.d(TAG, "New notifications found");
          mETag = lastEtag;
          return true;
      }
      return false;
  }

See the code here
Note that changing request method to GET fixes error, though makes such requests energy-inefficient

Expected behaviour

The HEAD request should properly work without throwing exception and/or crashing Nextcloud app

Actual behaviour

The Nextcloud app crashes showing the following report

Exception in thread "ParcelFileDescriptor Transfer Thread" java.lang.NullPointerException
    at java.io.SequenceInputStream.nextStream(SequenceInputStream.java:112)
    at java.io.SequenceInputStream.read(SequenceInputStream.java:211)
    at java.io.InputStream.read(InputStream.java:205)
    at com.nextcloud.android.sso.aidl.ParcelFileDescriptorUtil$TransferThread.run(ParcelFileDescriptorUtil.java:76)

App information

ID: com.nextcloud.client

Version: 30260090

Build flavor: generic

Device information

Brand: OnePlus

Device: OnePlus7TProNR

Model: HD1925

Id: TQ3A.230901.001

Product: OnePlus7TProNR

Firmware

SDK: 33

Release: 13

Incremental: PolarMod-1.3-r1-hotdogg-20231016_145036-user

Android version

13

Device brand and model

OnePlus 7T Pro 5G(hotdogg)

Stock or custom OS?

Custom

Nextcloud android app version

3.26.0(F-Droid)

Nextcloud server version

27.1.3

Using a reverse proxy?

Yes

Android logs

crash.log

Server error logs

[Sat Nov 18 19:28:20.147789 2023] [core:error] [pid 27955:tid 140288571983552] [client 100.64.22.27:53598] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:20.367436 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:20.445802 2023] [core:error] [pid 27675:tid 140287053657792] [client 100.64.22.27:53610] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:20.694604 2023] [core:error] [pid 27990:tid 140288991422144] [client 100.64.22.27:53612] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:21.068449 2023] [core:error] [pid 28025:tid 140289108854464] [client 100.64.22.27:53614] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:21.368670 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:21.380971 2023] [core:error] [pid 28026:tid 140287993181888] [client 100.64.22.27:53618] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:21.814248 2023] [core:error] [pid 28094:tid 140287649244864] [client 100.64.22.27:53628] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:22.369872 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:22.550135 2023] [core:error] [pid 28095:tid 140288253224640] [client 100.64.22.27:58026] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:23.371402 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:24.372663 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:25.373901 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:26.379545 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:27.380740 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:28.381905 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:28.855174 2023] [core:error] [pid 27710:tid 140288949458624] [client 100.64.22.1:60208] AH00082: an unknown filter was not added: Deflate
[Sat Nov 18 19:28:29.383183 2023] [mpm_worker:error] [pid 25117:tid 140289272453184] AH00288: scoreboard is full, not at MaxRequestWorkers
[Sat Nov 18 19:28:29.866286 2023] [core:error] [pid 28096:tid 140287540172480] [client 100.64.22.1:42815] AH00082: an unknown filter was not added: Deflate

Additional information

• The ROM in use is PolarMod which is slightly customized LinageOS(hardened malloc, minor UI customizations and bootloader lock support)
• Logs are partially provided due to private information stored in them
• HEAD requests seem to work without SSO
• Server logs are in EET time, device logs are in CEST time
• The issue with more detailed logs from side of application is opened in repository of my application