dav issue with subversion-1.7.18 and httpd-2.4.10

Upgraded a subversion-1.7.18 installation from http-2.2.28 to httpd-2.4.10 and running into strange issues.

Two clean builds (jail environment) with apr-1.5.1, apr-util-1.5.3, subversion-1.7.18, a) httpd-2.2.28 and b) httpd-2.4.10

No issues on httpd-2.2.28 or by using the svn protocol only via webdav (client independ)

Form the http-2.4.10 error log:

[Tue Aug 12 08:46:55.575078 2014] [dav:error] [pid 96427] [client 1.2.3.5:57266] Unable to PUT new contents for /svn/repo_abc/!svn/wrk/d6caf7c8-4701-0010-b3a9-ef26e25e095f/branches/Release_2014_08/file.name. [403, #0]

[Tue Aug 12 08:46:55.575126 2014] [dav:error] [pid 96427] [client 1.2.3.5:57266] Could not prepare to write the file [500, #200014]

[Tue Aug 12 08:46:55.575137 2014] [dav:error] [pid 96427] [client 1.2.3.5:57266] Base checksum mismatch on '/branches/Release_2014_08/file.name':\n expected: e02e545a6b7d4f347d6e8964db65e51e\n actual: 108b3c0ab68c457d8da178558187c3f9\n [500, #200014]

[Tue Aug 12 08:56:26.428469 2014] [dav:error] [pid 96427] [client 1.2.3.6:50011] Provider encountered an error while streaming a REPORT response. [500, #0]

[Tue Aug 12 08:56:26.428535 2014] [dav:error] [pid 96427] (32)Broken pipe: [client 1.2.3.6:50011] Error flushing brigade. [500, #0]

- switching from http(s)// to svn:// and the issue is no longer present.
- rebuild everything against http-2.2.27 everything is fine again.
- testing the repo with `svnadmin verify' shows no errors.

The issue is also present after a fresh checkout and modify one file, regardless the used client (1.7/1.8, native client, tortoise, svnkit, javahl)

Any hint where to start searching for the issue (latest httpd mod_dav changes or subversion missing backports)?

-- 
Regards,
olli