Trany shifting delay after my X5 parked overnight

[germangs]

I am experience a trany shifting delay after my X5 parked overnight or during the day when I get out from work. It’s just does not engage when I switch the gear do D and press the accelerator pedal for 5 seconds or so. It is not jerking or making any noises. It only happens when my car parked over long period of time. It is fine when I switch the gear to reverse to back it up but as soon as I switch the gear to D I feel that delay.
I tried to park my car front end first so I don’t need to switch the gear to reverse and I feel the same way. It is not engaging right away.
I was thinking maybe there is not enough pressure because it is low on Trany fluid.
It was properly checked and fluid level was fine. Besides that the trany is fine, shifts smooth without any hesitation.
Could you please tell me what I should do to get it resolve?