This reverts commit e441847ecae99dd1ccd0d9ce76dbcff51afa863c. A shallow copy is not enough because querysets can be reused and evaluated in nested nodes, which shouldn't mutate JOIN aliases. Thanks Michal Čihař for the report. Backport of 903aaa35e5ceaa33bfc9b19b7f6da65ce5a91dd4 from main