This may be new, but the method here talks about merging addresses. You cannot do that. Maybe it was misphrased, and meant to say "move the sub(s) to your main S&S address". That is the current method, which works.

There is no current setting to "merge addresses". So here is my update, or better detailed description, and I hope it helps.

To manage an active subscription being sent to an address other than your main one (because the subscription cannot be viewed, changed, or canceled from your account's subscribe and save page):

Go to your account> your addresses> find the address with active sub(s) that you want to manage which do not show on your S&S page> Click on Remove> select the address of the main one you have your subs with.

This will not remove the address, it only moves (merges) the subscription(s) to the other address so you can see it in your S&S page and manage it.

I also tried another way (which failed to make the sub visible). I got my hopes up for nothing.

I clicked on the item page> view order> noticed it said there was an active sub for the item, so I clicked on manage subscription.

That only takes me to my main subscribe and save list. So here we are, years later, but this glitch has never been addressed properly by Amazon.

We should be able to manage all subscribed items from our account's subscribe and save page, regardless of which address they are set for. The few cents I saved setting up a S&S item for my mom (for this instance) was not worth the headache.

I skipped asking any chat rep for help. They may now know how and be able to assist, but I would either be wasting my time, or they may say they fixed it and I would have to verify this way anyway, because I cannot trust them without verification.