Simply Turn Up With One Bridal Shower Gift by: Eunice
Showers may be given for second babies, but they should be restricted to very close friends and family, or to people not invited for the first shower. That is the general baby shower etiquette.
Obviously, the way the situation has been handled admittedly is in poor taste, but there is nothing you can do on your end as a guest.
On a practicality standpoint, combined showers are fine but NOT to the extent of asking your guests to bring two gifts. And also the second baby shower should be toned down a bit, or to have none at all (see above).
I suggest you simply turn up with a bridal shower gift and let that be that.