Added break statements to every case. This fixed issues we were having with this block in which the wrong header would be allowed through, sometimes seconds after start, sometimes hours after start, depending on the HPD settings used. With the break statements, general_work must be called each time a new state begins, which removes any sample offset issues that could be happening in the original fall through method. I suspect the original methods issue is caused by the check_items_available function, though I have not confirmed this. I've tested this fix against the current built-in block implementation in my own custom flowgraph, and in the rx_ofdm.grc example. The fix works in both cases.