There is no one to blame here. Shimano has been putting a Lip on the NDS since the UN53. The UN54 also shares the Lip. Every so many years Shimano makes a succesor to the UN5X ascending.
When I first tried a UN54, I ordered it online and did not realize the lip was there, as I had used UN72's in the past, which were good cartridge BB's with no NDS lip, and aluminum cups. Actually, I can see why Shimano would include the lip. Because at full torque spec., I found it to cause some drag in Shimano UN72's. To prevent this, I can see why they added the lip then. I myself, do not follow their spec.'s, I consider them recomendations, becasue no two BB's or frames are
precisely alike. Ever. Our bikes and parts are not truly precision instruments. There user always has to use their subjective mind to any application
So no one is to "blame"... ever. Okay, Shimano has it's reasons for doing as it does. Every user has their own expectations. If it's not working out, blaming doesn't make it work ! Refocus and assume you know exactly what to do, and it will come.
I, for one, am thankful for the experience as I discovered the quality Tange BB's, which are subjectively better in every way to the Shimano. I , like many people, didn't want to pay the extra few $$ initially thinking a BB was a BB, and "it's a Shimano, it will be alright". Okay, so it wasn't for me in this instance, it goes in my parts bin and I'll find a future use for it