Regression when cloning locally in 2.17.1-1ubuntu0.17

After installing the git update from 2.17.1-1ubuntu0.16 to 2.17.1-1ubuntu0.17 cloning from repositories clones by the repo tool does not work. This is seen on Ubuntu 18.04.

The repo tool created a git clone which looks like this (The repository is two times in the manifest):
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mehrtens@pon-swdev1:/local/mehrtens/pon/ugw-9.x/ugw_sw/openwrt$ ls -al /local/mehrtens/pon/ugw-9.x/ugw_sw/openwrt/../source/linux_prx//.git/
total 5948
drwxr-xr-x 2 mehrtens adusers 4096 Mar 6 11:08 .
drwxr-xr-x 28 mehrtens adusers 4096 Mar 6 11:18 ..
-rw-r--r-- 1 mehrtens adusers 44 Feb 24 14:25 COMMIT_EDITMSG
lrwxrwxrwx 1 mehrtens adusers 61 Jan 26 17:35 config -> ../../../../.repo/projects/ugw_sw/source/linux_prx.git/config
lrwxrwxrwx 1 mehrtens adusers 55 Jan 26 17:35 description -> ../../../../.repo/project-objects/linux.git/description
-rw-r--r-- 1 mehrtens adusers 217700 Mar 2 10:20 FETCH_HEAD
-rw-r--r-- 1 mehrtens adusers 22 Mar 6 10:56 HEAD
lrwxrwxrwx 1 mehrtens adusers 49 Jan 26 17:35 hooks -> ../../../../.repo/project-objects/linux.git/hooks
-rw-r--r-- 1 mehrtens adusers 5838812 Mar 6 10:57 index
lrwxrwxrwx 1 mehrtens adusers 48 Jan 26 17:35 info -> ../../../../.repo/project-objects/linux.git/info
lrwxrwxrwx 1 mehrtens adusers 59 Jan 26 17:35 logs -> ../../../../.repo/projects/ugw_sw/source/linux_prx.git/logs
lrwxrwxrwx 1 mehrtens adusers 51 Jan 26 17:35 objects -> ../../../../.repo/project-objects/linux.git/objects
-rw-r--r-- 1 mehrtens adusers 41 Mar 2 19:05 ORIG_HEAD
lrwxrwxrwx 1 mehrtens adusers 66 Jan 26 17:35 packed-refs -> ../../../../.repo/projects/ugw_sw/source/linux_prx.git/packed-refs
lrwxrwxrwx 1 mehrtens adusers 59 Jan 26 17:35 refs -> ../../../../.repo/projects/ugw_sw/source/linux_prx.git/refs
lrwxrwxrwx 1 mehrtens adusers 52 Jan 26 17:35 rr-cache -> ../../../../.repo/project-objects/linux.git/rr-cache
lrwxrwxrwx 1 mehrtens adusers 47 Jan 26 17:35 svn -> ../../../../.repo/project-objects/linux.git/svn
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When I clone this local git repository I am getting this error message:
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mehrtens@pon-swdev1:/local/mehrtens/pon/ugw-9.x/ugw_sw/openwrt$ git clone ../source/linux_prx/ linux-test
Cloning into 'linux-test'...
fatal: failed to start iterator over '/local/mehrtens/pon/ugw-9.x/ugw_sw/openwrt/../source/linux_prx//.git/objects': Not a directory
fatal: The remote end hung up unexpectedly
mehrtens@pon-swdev1:/local/mehrtens/pon/ugw-9.x/ugw_sw/openwrt$
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When I use git version 2.17.1-1ubuntu0.16 it works.

As a workaround we now downgraded to git version 2.17.1-1ubuntu0.16 and it works again.