I haven't seen RWS caps for decades.
Back around 1970, when I first got into black powder, we only had one local dealer that handled shooting supplies for black powder.
Don't remember the name, but the powder he sold was made in Scotland, and it caused the nastiest, greasy fouling I have ever seen, and he only had Navy Arms caps.
The cap tins had a Navy Arms sticker on the top, which covered the RWS logo.
As you say, the caps always exhibited bulges and perforations. Worse, they often fragmented badly, causing the revolvers to jamb with fragments, and a large percentage of them would weld to the nipple.
Cutting and twisting welded caps off nipples with patch knife and needle nosed pliers almost made me give up on the sport.
I would have thought RWS would have improved them after 40 years ?
I finally found a gunshop 40 miles north of me, that handled Remington caps, and good old Dupont Superfine powder, which made the game a lot more fun.
I sure wish Superfine was still being made !!!!