Turning the phone from portrait to landscape unfreezes it only for a few seconds and it seems that there is no reliable solution for this available right now as it’s probably an issue with AppSupport. The latest Here We Go app has the same issues.
However, using an older version of Google Maps (something from the v11 branch) works perfectly fine for me. At least until Google decides to kill support for such old versions. So it would be really nice if the Jolla devs could investigate the root cause for such issues.