I've had the same issue twice. The first time I thought it was a one-time bug, so last night (June 12th) I logged out and back in every 30 minutes or so and it seemed like it was saving progress. Logged out for the last time around 10pm, and just logged in again today (June 13th) around 8:15pm. About half of my progress has been lost from last night, and some of that progress I had confirmed by logging out and back in.
I've had the same issue twice. The first time I thought it was a one-time bug, so last night (June 12th) I logged out and back in every 30 minutes or so and it seemed like it was saving progress. Logged out for the last time around 10pm, and just logged in again today (June 13th) around 8:15pm. About half of my progress has been lost from last night, and some of that progress I had confirmed by logging out and back in.