Congrats on building a couple of nice gliders. For glider one, check to see if the fllaps are bent down exacltly the same. One mm difference at any point alongthe flap will affect turn. Also check to see that the right wing and left wing are equal in weight (balance the fuselage on a finger of each hand to see if one wing hangs down). Sandthe heavier wing till corrected. A small 1/16" ball of clay on the wingtip can aid turn.
The second glider sounds like it needs some wing incidence. This can be accomplished by adding a 1/32"shim between the fuselage and the wing mount forward of the wing leading edge (remove front tape, install shim of hard balsa or the like, apply a newpiece of tape) .
Give more details and i can provide better help (ex. Amount of flap deflection, wing incidence, center of gravity location, bank angle and inclination angle of launch, weight of gliders) .
AMA since 1972