Pip cache directory owned by root on s390x

The /home/travis/.cache/pip/wheels directory is owned by root on s390x, which is preventing me from installing Python packages unless I use the --no-cache-dir flag. This is the contents of ~/.cache/pip on s390x:

$ ls -l ~/.cache/pip/
total 13
drwxrwxr-x  7 travis travis  7 Jan 20 10:42 http
drwxrwxr-x  2 travis travis  3 Jan 20 10:42 selfcheck
drwxr-xr-x 10 root   root   10 Jan 20 10:45 wheels

And AMD64, for comparison:

$ ls -l ~/.cache/pip/
total 12
drwx------ 15 travis travis 4096 Mar 25  2019 http
-rw-r--r--  1 travis travis  550 Mar 25  2019 selfcheck.json
drwxr-xr-x  3 travis travis 4096 Mar 25  2019 wheels

Here’s a build that shows the issue: https://travis-ci.org/spacetelescope/asdf/builds/641142620

Is this the right place to submit a bug report? Let me know if I should post this somewhere else. Thanks!

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