I concur that it is typical behavior.

This effect is more pronounced on cold days.

This happened on my first transmission and also on my second transmission.

The second transmission has also always shifted weird from first into second no matter how warm the engine and transmission are. It's like a weird pause when shifting.

 

I had the similar problem I just changed over to Max Life synthetic transmission fluid I got it at Wall Mart, I drained the trans thru the drain plug and refilled it thru the filler tube. I did this 4 times to get a good total fluid
change out I also got some fiber washers at Toyota and used them at each time I drained the transmission. If you can DIY I would change the transmission filter it is most likely dirty and won't let the fluid flow
easily also the reason for the synthetic fluid it flows better in the cold and holds up much better in the heat. I only have 148,000 miles on the RX clock I put over 500,000 miles on a Toyota Cressida and 400,000 miles on a LexusLS400 using all synthetic fluids in the power steering and motors and nothing ever wore out.

 

I asked the same question as the OP when I thought this was an issue in my car.

See my thread: https://www.clublexus.com/forums/rx-...is-normal.html