Trading profits and losses are not a fundamental part of a banks earnings and are subject to volailitiy. JPM has a great track record of trading. Their earnings power is still phenomenal and this is a one-time event, and it reduces their book value by like 1%. IMO, a PERFECT time to jump in on a sell off that was way unwarranted.
Also a good time to buy other banks that sold off too on this news, as it does not affect them.