Continue receiving "Invalid Credentials" error

[ajdubovoy]

For some reason, Spotify seems to OK the login, but Rails pulls an "Invalid Credentials" error on the callback. This happens about ~70% of the time, but somewhat at random with different users. We've already tried downgrading the omniauth-oauth2 1.4.0 gem to 1.3.1 (as per #211).

We've also tried implementing: omniauth/omniauth-oauth2@2615267#diff-1894759d724182a93ca97be91b43a7bc. But it didn't change anything sadly :(

Would hugely appreciate any help!