I think limit is still persisting (I removed from config storage2.max-concurrent-requests) and after storagenode upgraded to latest version see this on log:
docker logs storagenode 2>&1 | grep rejected
2019-11-07T20:01:27.060Z ERROR piecestore upload rejected, too many requests {“live requests”: 9}
2019-11-07T20:01:28.599Z ERROR piecestore upload rejected, too many requests {“live requests”: 9}
2019-11-07T20:01:30.996Z ERROR piecestore upload rejected, too many requests {“live requests”: 8}
2019-11-07T20:02:54.721Z ERROR piecestore upload rejected, too many requests {“live requests”: 8}
2019-11-07T20:12:28.007Z ERROR piecestore upload rejected, too many requests {“live requests”: 8}
2019-11-07T20:12:28.461Z ERROR piecestore upload rejected, too many requests {“live requests”: 8}