Currently since a pair of months, I've been using a 150/600 Newtonian refractor with the needed coma corrector (the GPU TS-Optics one) with an ASI533MC OSC and the EAF for focuser. After a detailed examination of the images, I've seen that the coma corrector adds a considerable amount of chromatic aberration. The fast f4 focal ratio means that I've a very shallow focus region, so the focus shift introduced by the chromatic aberration is enough to destroy almost completely the blue Chanel. On the next image, you can see the 4 channels extracted from the CFA



0 = Green, 1 = Red, 2 = Blue and 3 = Green

You can see that the red is the most focused image followed by the green and lastly the blue. I suspect that Ekos is using the red channel to analyse the focus. It will be more useful if the green image where used. This way, the aberration will be best controller, because red and blue will have the same amount of aberration from green, instead of a big error on blue channel.

Nobody has the need to use a concrete channel on a OSC for focusing? Nobody has experienced this behaviour? I mean, it's very odd, with the amount of OSC & DSRL cameras coupled with non perfect APO telescopes out there, that nobody has observed this problem before.

As this problem seems to be more Stellarsolve related that Ekos related, I've created a new post on the Stellarsolve 2.0 thread. You can follow it on indilib.org/forum/ekos/11388-announcing-....html?start=36#82599

Regarding your Coma Correction aberrations. You probably need check the back focus distances from it to your sensor.
At 600mm, your CC specifies 51.5mm back focus.
The ASI 533 has 17.5mm from the M42 T-thread. So you need to make up 34mm in spacers.