Sorry for the long dissertation:
I am using version 6.21: 00. Number of retries is set to 0=infinite in options. NBP is ignoring missing blocks without trying to re-download the blocks. It assembles the files with missing blocks resulting in corrupt files or insufficient blocks for a manual QuickPar repair.
I know NBP sees missing blocks because red blocks appear in the current progress column and I know it ignores the infinite retry set in options because when the last block is downloaded, the posting disappears from the download list. I know that the blocks are on the server because if I force NBP to retry the download before the file disappears, by clicking the "Retry the Download" icon, the red blocks go white, the download of the blocks is attempted again, and the block is eventually downloaded (Sometimes it might take 3 clicks of the icon for each missing block). Currently I am unable to download anything of significant size unless I sit and watch the download (zzzz) for the red blocks and force the retry download but who has time for that. I believe this started with my last update of NBP. Can anyone offer some solutions?