Thanks for your replies. I am quite active in adding coverart, but this is not the full solution. Sometimes I prefer a different cover and the ASIN to digital copies does not pull the coverart.
Yes, I have "clear existing tags" enabled, but I still do believe this is a bug. Also, if you take a look at the other thread that I have linked, it is confirmed that there is a bug.
I am working based on a nightly built, which includes fantastic changes to coverart. Unfortunately, it does not solve the issue I am describing here. As you can see from the other thread, there may be a fix available, but it requires someone to test before it goes to the nightly built. I would be happy to do so, but don't know how to compile.
I have not tried adding APIC. Does this address the issue?