Not sure if this interaction was even intended originally, but Shadowstrike (+25 aim & crit or +50 aim & crit with LW2 Classes & Perks) applies to all enemies that can't see you. This includes both concealment and Squadsight. My suggestion would be leaving the concealment bonus as is and dividing the bonuses by 2/3 for Squadsight shots.
Edit:
Conclusion: Lower buff to +10/+10 at Squadsight range.
Not sure if this interaction was even intended originally, but Shadowstrike (+25 aim & crit or +50 aim & crit with LW2 Classes & Perks) applies to all enemies that can't see you. This includes both concealment and Squadsight. My suggestion would be leaving the concealment bonus as is and dividing the bonuses by 2/3 for Squadsight shots.
Edit:
Conclusion: Lower buff to +10/+10 at Squadsight range.