Custom awb_gains not working

[JolleJolles]

I am trying to set custom gains and created the following script based on the picamera documentation

`from time import sleep
from picamera import PiCamera
from fractions import Fraction

camera = PiCamera(resolution=(1280, 720), framerate=30)
camera.iso = 100
sleep(2)
camera.shutter_speed = camera.exposure_speed
camera.exposure_mode = 'off'
g = camera.awb_gains
camera.awb_mode = 'off'
camera.awb_gains = (2.5, 2.5)
camera.capture('try.jpg')
print(camera.awb_gains)`

But whatever I put as camera.awb_gains, also with Fractions, the values returned are always very similar fractions in the range (Fraction(167, 128), Fraction(257, 128)). The images returned also always have a nice white balance and not the overly red or blue that I would expect with the provided awb_gains.

I am testing this on a rpi 3B+

Originally posted by @JolleJolles in #318 (comment)

[JolleJolles]

I could fix it by adding sleep(0.1) after setting the awb_gains