I'm also having this issue. Financial reports for May 2017 have been released today. Proceeds are well beyond the 150$ threshold, and it says "Balance carried forward".
The same thing happened last month.
I can provide the following additional information:
Last month, looking at the contracts section, I found that there was an amendment for Paid Applications which I had not agreed upon. There was no notification of any sort from Apple about this amendment. After agreeing, the payment reports were updated to reflect the previous month's actual proceeds the next day, and payment was carried out, however with a delay of a week - usually payments are performed at the end of a month, but I received the money a week later. So that was the previous month.
This month, I am seeing the proceeds in the new reports, balance carried forward, and again there was a silent Paid Applications contract amendment without any notification. I just now agreed to it again, hopefully the payment will be carried out.
This seems like a severe issue tbh - no idea what's going on.