Failure about unzipping the demo_1k.zip

[ergo-zyh]

Dear, I fail when I unzip the demo_1k.zip after I run the command cat demo_1k_part* > demo_1k.zip_. And the error appears like

Archive:  demo_1k.zip
fatal error: read failure while seeking for End-of-centdir-64 signature.
  This zipfile is corrupt.
unzip:  cannot find zipfile directory in one of demo_1k.zip or
        demo_1k.zip.zip, and cannot find demo_1k.zip.ZIP, period.

And I use the command
7z x demo_1k.zip
the error appears
62ERROR: Data Error : demo_1k/StackCube-v1/motionplanning/3/99/61.png
Do you meet the problem? Is there any wrong thing or I run it wrong?
Thanks

[LBG21]

Hi, we're currently reviewing the files to ensure if there's any file missed. We should have this resolved shortly and we'll update as soon as possible.

[ergo-zyh]

Hi, we're currently reviewing the files to ensure if there's any file missed. We should have this resolved shortly and we'll update as soon as possible.

Thanks a lot.

[LBG21]

Hi, it appears that the files are correct and complete. You can try re-downloading these files.

[ergo-zyh]

Thank you for your help. I have verified the SHA256 and the size of each file, and they are all correct. I'm unsure about what could be causing the issue.

[LBG21]

I'll try re-upload these files.