Firefox: 2nd survey answer sometimes not logged

[dhmquan]

In Firefox, sometimes the radio choice of the 2nd question in both pre- and post- surveys are not logged. This confounds me as whenever I ran the debugger on the relevant function - storeAnswer() - it runs as expected.

I suspect that there's some problem with asynchronicity here, though the bug still didn't go away after I re-implemented the functions with async/await.