Yes but he’s using the Wiim in both scenarios which could be both lossy. Compare through the Wiim and then without
WiiM confirmed to me a while ago that they currently don’t support lossless Amazon Music whether that be 16 bit HD or 24 bit UHD - that’s what they’re developing and targeting for 15/5, although it looks like that will slip.
Amazon Music historically has been lossy MP3 and supported on a range of kit. When lossy Amazon Music HD was released, support for it was, and still is to an extent, sporadic as Amazon perversely seem to go out of their way to make it hard for third parties to support it.
As I think I’ve posted in this or the other big WiiM thread, you can think of the current Amazon Music service having three quality levels: lossy SD, lossless 16 bit HD and lossless 24bit UHD. What initial implementations of Amazon Music support is the first (from what used to be called the Amazon Music Unlimited service) with support for both the second and third (from what was released separately as the Amazon Music HD service) being the uphill struggle. I also believe that the two services have different APIs, levels of certification and even delivery mechanisms (e.g. the use of adaptive bandwidth for the HD service).
Where I think the confusion has arisen is that lossy SD tracks also present as 16/44.1 from WiiM, as would a lossless 16/44.1 HD (CD quality) track. To be honest, I think some of the WiiM information on their website isn’t helpful where even they have confused 16bit as solely HD and talk about developing support for UHD alone.
I strongly contend that WiiM currently only supports the first quality level of Amazon Music, and are working on the second and third, not that they currently support the first and second.