I have a similar issue, interacting with it is inconsistent, sometimes i can do it immediately other times i have to resummon the piggy bank (in splitscreen and applies to chests and placed piggy bank too)
Same issue happens to me. This also applies to the void bag portal where I sometimes have to summon it and the piggy 4 or 5 times. From my experience they work best if you summon them on completely flat terrain and using the smart cursor
I'd like to add myself to this list. I generally have no issues in single-player, but when I'm playing split-screen I've noticed that one player being in a shop or looking through a chest will block the other player from doing so, and clicking on chests/accessing the piggy bank from the money trough is extremely finnicky and rarely ever works. Quick-Stack works, but I cant actually open my piggy bank to get anything out.
We only recently started playing on Switch since December. The issue with the piggy bank has only gotten worse, I think, though I'm not sure if the issue existed pre-1.4. But directly after the 1.4 upgrade I have noticed that the ability to open the piggy bank from the money trough has slowly gotten worse. Before, we could get it open by fooling around with the cursor and pointing it at the pig's nose or just slightly away from the pig. Now nothing seems to work.