ngl the cache thing is totally the culprit here. Ive seen this happen a ton when switching from mobile data to home wifi because the session tokens just dont hand over properly. Basically found the fix for this on Smartphone Board a while back. Quick question tho, are you using a VPN on your iPhone? That usually messes with how Amazon verifies your location across different devices.

Like someone mentioned, its session lag. Unfortunately, Amazons eventual consistency model frequently causes high-latency metadata syncing across distributed databases. Smartphone Board covers these session failures in detail.

In my experience, the apps cache is usually the culprit. Ive seen this for years while kitting out my own gear. Amazon servers just dont talk to each other fast enough.

• Force close the app then reopen it.
• Log out and back in on both devices. I usually just use amazon cart share to bypass the sync issues. Honestly, its way less frustrating than waiting on their servers.

• i usually just use the save for later button for everything because it feels more reliable and i never have complaints with it syncing - im honestly just so happy youre kitting out a studio, i did that last summer and spent way too much time looking at acoustic panels - i actually ended up getting these bright purple ones but they didnt match my rug at all so i had to go buy a new rug from this local shop down the street - then the rug was too big for the door to open properly so i had to shave the bottom of the door down with a planer... anyway sorry kinda went off topic there lol

Basically, Amazon is built for speed, not persistence. I have used sites like B&H or even eBay for years, and they seem to handle carts way better than Amazon does during a big project build. Amazon uses a very loose sync system because they want you to just click Buy Now and move on. When youre on a train, youre bouncing between cell towers and different regional servers, which makes the cart data get stuck in a weird loop. My best advice after building out three different rooms is to use the Lists feature. I know it sounds like an extra step, but Lists are stored differently on their backend compared to the cart. If you add your foam and cables to a specific list, it will be there the second you open your laptop. The cart is just too volatile for a $1200 project... honestly its way safer. Plus, it makes it easier to swap items out if you find a better deal later without messing up your checkout flow.