Perhaps older vendors aren't handling the hash properly?

I've noted that swarmed downloads are still troublesome, especially when they don't grow sequentially. Vendor seems to be the variable here.
For example, after starting to download a 118.2 MB .mpg file, I noticed in the
Library tab > Incomplete download showed the file at 59MB, then it jumped within a few seconds to 91MB after it started swarming from another source, vendor/version LimeWire 2.3.4. It kept growing every few seconds by a few k.

Swarmed for a while from 2 hosts, then it stalled after a few hours. Then another file of the same name + 1 showed up in the incomplete list (no additional download clicked in Search pane). Both files grew to >100MB of the 118.2 MB listed over the next few hours. Then nothing for a few more hours. Occasionally other clients would continue the download for a while, then LimeWire 2.3.4 showed up again and continue at a slow but steady 1 or 2 KB/s. The progress bar (at ~75%) slowly kept growing, even though the file sizes in the Library>incomplete display didn't change. One showed the original file at the full 118.2; the other at 106.2MB. Don't know which file was being "filled up." After about 27 hours, the 106.2 started growing again, and successfully completed in 28 1/2 hrs at an av of 4KB/s. The Txxxxetc.mpg , was choppy when played, but seemed to have all the scenes.

I'm hoping older vendors are the problem rather than malicious hosts. Could spammers fake the file size displayed?