Can someone explain why my OS won't come out?

It’s been a while since I’ve done much training mode, so I thought I’d go and practice some stuff including basic safe jump option selects.
I’ve gotten myself into this situation where I knock the opponent down with Sakura’s MP Shouoken and hold up/forward and push a button for a 5 frame safe jump.
I’m going against Adon and the safe jump is working, but whenever I try to input say an ultra or a backdash if he does an HK rising jaguar, instead I just get hit or I block and my inputs are all eaten up.
Anyone got a good explanation of why this is happening?

You’re timing it wrong. If you input it too early then nothing comes out, but if you input it too late, then your os will come out even if your attack connects.

Either that or your safejump isn’t fast enough to allow inputs because of the few frames of landing recovery.