Gao Jue did poorly on his job interviews at J.P. Morgan Chase & Co., he messed up his work visa, accidentally sent a sexually explicit email to a human-resources employee and was described by a senior banker as “immature, irresponsible and unreliable,” according to internal bank emails and people familiar with the matter.

Yet the bank hired him, saved him during major job cuts and later was prepared to offer him another position if he had responded to their queries.

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