One year already 
Since, no solution worked for us, we did another debug session in the last few days.
The problem was caused by “Just Links” triggers with “Wait for Tags” enabled.
As soon as one of these triggers exists, the gtm.js script will start mimicking the click (location.href = $clickedLink.href), regardless of whether the wait limit is exceeded or not. At the same time preventDefault is called.
For our project, it was fine to either delete the trigger or disable “Wait for Tags”, so we finally got it working.
