The initial value for the directional parameter SETTINGS_MAX_CONCURRENT_STREAMS, in the direction from the server to the client, is incorrectly limited to 100, when there should be no initial limit.

From section 6.5.2. Defined SETTINGS Parameters:

 SETTINGS_MAX_CONCURRENT_STREAMS (0x3): Indicates the maximum number
      of concurrent streams that the sender will allow. This limit is
      directional: it applies to the number of streams that the sender
      permits the receiver to create. *** Initially, there is no limit to
      this value***. It is recommended that this value be no smaller than
      100, so as to not unnecessarily limit parallelism.

      A value of 0 for SETTINGS_MAX_CONCURRENT_STREAMS SHOULD NOT be
      treated as special by endpoints. A zero value does prevent the
      creation of new streams; however, this can also happen for any
      limit that is exhausted with active streams. Servers SHOULD only
      set a zero value for short durations; if a server does not wish to
      accept requests, closing the connection is more appropriate.