When using the backup sights on the SOS, DMS and Nightstalker optics, there will be a certain amount of blur present towards the edges of the screen.
This blur seems to be intended for the main, zoomed in sight, but persists after you switch to the short range backup sights.
Backup sights on ARCO and RCO do not exhibit this problem, but their zoom optics don't have the blur either.
It's expected that the blur will only be present when using the main, zoomed in optic, but not when using the backup sight.
If it's not possible to separate the blur settings between the two optic modes, I suggest removing the blur from the main optic as well so it's like the ARCO and RCO as the blur is barely noticeable in the zoomed in optics but it's really making the backup optics inferior to the other red dot sights for no good reason.