'97 Chevy k1500 5.7 auto - First gear shift delay shift to second and no codes?

So I have ran into a situation that has stumped me and
before I plan to start throwing parts and money at this
thing, I wanna hear from you.
Truck has 175k and I'm not aware of any previous
transmission work done to it for I purchased about 2
months ago.
The truck has just started having a delayed first gear until
about 3000 rpm then shifts normally into second and is
fine after. Does not slip or give a hard shift into second
either. instantly went to check fluid and to find it clean
(previous owner was a close friend and did tranny flush
about 6 months ago) and fluid was red and wiped with
white rag and was clean. Later checking to fluid after
class it was still clean but had few bubbles on dipstick is
this normal? Next I went looking for codes to find none.
I've stil been driving it the past few days to school and
work and that consists majority highway driving and it
does go into overdrive and drives as should after first gear
So I guess the question is, am I losing first gear? Or could
a defective shift solenoid delay a shift and still not throw a
Trouble code? I need your help with any advice or tips
that could save me money and time.  Thank you!