I've seen this behaviour when the page you want to PiP to is scrolled to but not actually selected or the selected page isn't fully on-screen, iow, the page you are pasting 'too' isn't the only page you can see on your screen when zoomed to 100%. This causes the pasted object to jump back to the previous page as you say.
This is different to v3.2 and probably a bug as mentioned..
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