Sorry, those are incomplete downloads, here’s what it looks like from my side. I just downloaded the files for comparison:
[user@host]:~/Downloads/isos-truenas$ ls -l
total 5769176
-rw-r--r--@ 1 user group 1626347520 14 May 12:34 TrueNAS-SCALE-24.04.0.iso
-rw-r--r--@ 1 user group 1316044800 14 May 12:34 TrueNAS-SCALE-24.04.0.update
[user@host]:~/Downloads/isos-truenas$ shasum -a 256 *
9ab42b900894ecc2a0a46c598807bf6e493f53bee7d61ff321030fa4ff5f1a11 TrueNAS-SCALE-24.04.0.iso
10705da248f9d7a4eb5f24056cbd15262b144cfa3e2256088db353c1c0f26377 TrueNAS-SCALE-24.04.0.update
Note the bigger file sizes. 1626347520 bytes vs your 1085683520 for the 24.04 iso, as an example.