this mughal jade cup, it's "瓜瓣瓢" or "瓜辨瓢"?
Looks like it should be 瓜瓣瓢.


瓜瓣瓢 probably means a 瓢 made from 瓜瓣. In contrast, 瓜辨 is not a word (AFAIK).
See a printed version of 清・金士松《喬羽書巢詩集》 (https://ctext.org/library.pl?if=en&amp;file=105725&amp;page=51). Since your screenshot looks like it's from a handwritten version of 《御製詩四集》, I suspect that it's a handwriting error. Well, printing is less likely to introduce errors :)