When he decided not to run in CA-26, it was logical that CA-25 was his goal. He'd raised a lot of money and wouldn't have gone through all that work if he didn't intend to run for congress in some district. He couldn't keep his campaign fund designated for CA-26, as that'd undercut Jeff Gorell. Changing the designation doesn't indicate he's running for CA-25 this cycle. It's more likely that he's planning on running when Buck McKeon retires, whether that's this cycle, next, or down the road. Now he can continue fundraising for that goal.
Edit: It appears that I'm right and Strickland is waiting for McKeon to retire.