Some encrypted Series files don't extract - need to CAT then p7zip them

[phillwall72]

around 90% of series files are not extracting. These are items without PATR files, and the log says (Series name changed to ABC):

INFO | Wed Oct 12 2022 10:44:33 | Collection ABC added to history
INFO | Wed Oct 12 2022 10:44:33 | Move for ABC successful
INFO | Wed Oct 12 2022 10:44:33 | Moving file [6_6] - 6da53aaaf5aa288262dca8d0123ae611 yEnc 31969562 (1_45) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving file [5_6] - 7e5352c1cc4ca4c7377527a8b96b03bb yEnc 104857600 (1_147) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving file [4_6] - a8c4fbc2673dd7942232fe7d39e698b8 yEnc 104857600 (1_147) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving file [3_6] - dbaccffa038a89b1bd109ac0833c34eb yEnc 104857600 (1_147) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving file [2_6] - afff20979511a1df64f6ed9bc7e5f688 yEnc 104857600 (1_147) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving file [1_6] - bc5f2a40d7c96c5fcb663da54b7e6388 yEnc 104857600 (1_147) to /downloads/completed/Series/ABC
INFO | Wed Oct 12 2022 10:44:33 | Moving completed files for ABC
INFO | Wed Oct 12 2022 10:44:32 | Nothing to cleanup for ABC
INFO | Wed Oct 12 2022 10:44:32 | Cleaning up ABC
INFO | Wed Oct 12 2022 10:44:32 | Nothing to unpack for ABC
INFO | Wed Oct 12 2022 10:44:32 | No renamed archive files found for ABC
INFO | Wed Oct 12 2022 10:44:32 | Checking renamed archive files for ABC
INFO | Wed Oct 12 2022 10:44:32 | Nothing to par-check for ABC
INFO | Wed Oct 12 2022 10:44:32 | No renamed files found for ABC
INFO | Wed Oct 12 2022 10:44:32 | Checking renamed files for ABC
INFO | Wed Oct 12 2022 10:44:32 | Queueing ABC for post-processing
INFO | Wed Oct 12 2022 10:44:32 | Collection ABC completely downloaded
INFO | Wed Oct 12 2022 10:44:32 | Successfully downloaded ABC/[6_6] - 6da53aaaf5aa288262dca8d0123ae611 yEnc 31969562 (1_45)
INFO | Wed Oct 12 2022 10:44:24 | Successfully downloaded ABC/[5_6] - 7e5352c1cc4ca4c7377527a8b96b03bb yEnc 104857600 (1_147)
INFO | Wed Oct 12 2022 10:43:59 | Successfully downloaded TABC/[4_6] - a8c4fbc2673dd7942232fe7d39e698b8 yEnc 104857600 (1_147)
INFO | Wed Oct 12 2022 10:43:35 | Successfully downloaded ABC/[3_6] - dbaccffa038a89b1bd109ac0833c34eb yEnc 104857600 (1_147)
INFO | Wed Oct 12 2022 10:43:13 | Successfully downloaded ABC/[2_6] - afff20979511a1df64f6ed9bc7e5f688 yEnc 104857600 (1_147)
INFO | Wed Oct 12 2022 10:42:44 | Successfully downloaded ABC/[1_6] - bc5f2a40d7c96c5fcb663da54b7e6388 yEnc 104857600 (1_147)
INFO | Wed Oct 12 2022 10:29:18 | Reordering files for ABC
INFO | Wed Oct 12 2022 10:29:18 | Collection ABC added to queue

I can manually extract by cat-ing the files together to a new file called file.7z and then running p7zip -d on the file and use the password stored in nzbget - but not sure why this should be happening so much now - Seems every series I down load does this.