Happens all the time with shady third-party manufacturers in countries other than your own.
You get a perfectly nice sample unit that meets all specs and looks beautiful. When the container arrives off the boat with 100,000 production units you find materials have been substituted with cheaper materials, scrap plastic, and scavenged components.
Walk into any dollar store and you'll smell something similar to this, cheap plastics off-gassing all kinds of wonderful substances. I picked up a flashlight once that literally smelled of kerosene, probably because that's what the overseas factory used as a plasticizer to get that "rubbery" feel on the handle.
You can get the same smell from the 99 cent set of black soft plastic measuring cups and spoons at Wal-Mart. I'm surprised anybody buys and uses those; no doubt it affects the taste (and possibly safety) of whatever they measure.
That happened at a former employer of mine. Parts came in covered in chicken shit and straw. Long story short: our main vendor in China outsourced to a make-shift forging operation set up in a barn.
Thermoplastic manufacturing is crazy. There's no end of chemical additives used for variant purposes, and substitutes for them for certain usages. Apparently this batch discovered some new chemistry and there was no QA process in place to catch it.
Probably cost cutting gone wrong. Lots of acidic chemicals are used and they need to be carefully washed off parts or the smell will linger. Many cheap glues/tapes can also carry a strong acidic smell. The comparison to cat urine makes sense since the smell comes from its high acidity.
