727 Hard Shift from 1st to 2nd...smooth into 3rd

Yeah, somebody put the wrong spring in the 1-2 valve, or its stuck, or the accumulator is stuck or blocked. That'd be my guess. In any case,the VB needs to come down.
Unless the 2-3 shift is also way early. Then there could be multiple problems.
On further pondering; I suppose the line-pressure could be cranked, as well as the throttle pressure, and the 2-3 is wrong.
Same conclusion; VB needs to come down.

In any case TB is on the money.

I was going to guess blocked accumulator or the line pressure is just too high.