since then nothing has changed
It just changed:
Previously, I was under the impression that Jambler was merely a software or platform provider, like Wordpress or AWS. But after reviewing it more closely, it meets the definition of a mixer as written. My mind was especially changed when I saw this diagram from their website:
The diagram clearly shows that Jambler is the actual mixer. They issue the "letters of guarantee", they send the BTC directly to the final customer, etc. The partners are just lightweight proxies in front of the true mixer, which is Jambler. Jambler "has a feature advertised for taking property, improving its privacy somehow, and then returning roughly the same type of property", and it meets the other two criteria, so it's a mixer.
(Maybe you could make the case that Jambler's actual customers are its
partners instead of the final end-users, but even in that case Jambler is acting as a mixer for its partners. Jambler is the one doing the mixing. So it's still a mixer in either case.)
Since I had previously ruled that Jambler did not meet the definition of a mixer, and I've now changed my mind, there will be a short grace period:
Jambler will be wordfiltered (and otherwise treated as a mixer) starting on April 22.
As with other banned mixers, please do not interpret this as a
moral judgement. I'm not saying that Jambler is or is not
bad.