1) Clicking floating menu bar links before page is 100% loaded
When you load a new page, the menu bar at the bottom (My Page, Fusion, Summon, etc.) appears in the middle of your page before it has finished loading, and the links are active. So if you click on a link and the menu loads and you click on something on the page quickly, you're at risk of clicking the menu links by accident (they don't even have to be visible yet and sometimes the link is still active) and being booted to a page you didn't intend to go to. I can't tell you how many times I have been kicked to the shop or summon page because I was moving quickly while playing the app. I did notice that once the menu becomes visible at the bottom, I have never had this problem; but if you move too quickly, you are at risk of clicking the links whether they are visible or not
it only gave me the option to continue. The cards did not show up in my inventory either.
This may be working as intended but it would be a massively helpful addition towards making the game more pleasant and convenient, rather than just losing out on gold when you have no more room for the normals (when you don't realize it's full). Even if you know you have to make room to gather more normals, you still have to spend many clicks backing out and selling cards so that you can return. For those of us with very full lists, you might not have much more than 10 spots or so for normals at any given time, so it doesn't take long to fill up your inventory and then you have to go back and sell before long. Very inconvenient.
If this is working as intended I think a good compromise would be: If you have 49/50 monsters and you have just encountered the 50th, instead of the "Sell & Continue" button, simply have a "Sell" button that would boot you to the regular Sell screen that allows you to select all the cards you need to sell via check boxes. This would not only be faster and more streamlined, but it would help remind players that their list is almost full as well, making the process less frustrating.