I'll take a guess that the system calculating Vls is using the current AoA as a means to determine the current effective weight of the aircraft.
For example, suppose my stall speed is at 10 alpha and zero lift is at 0 alpha (arbitrary numbers, I know they are wrong).
In S&L flight, I may be flying at 6 alpha. So my system decides I'm flying at a CL equal to 6/10ths of stall CL. That means, assuming a linear CL-alpha curve, I'm 1/square root(0.6) above stall speed. So I can use my current airspeed and divide by that stall speed factor, to get my predicted stall speed. Then I can multiply that predicted Vs by 1.28 to get Vls.
Now, enter a turn at the same airspeed. Because I'm at 'g', I'm now at 7 alpha. So the system now sees that I'm at 1/sqrt(0.7) times stall speed, which means, since my actual speed is the same, my predicted stall speed is higher. So my Vls also increases.
Basically, the Vls value isn't 'g'=compensated.
(Based on the 'FAA green line' logic in our own a/c, which behaves exactly like this)