Light lures are the hardest thing to cast cleanly on a baitcaster because the spool turns faster than the lure can pull line off it. The result is the spool over-revving on the downswing and the line piling up on the spool in a bird's nest. The fix is not "cast more carefully." It is four changes in a specific order. Apply them in that order and your light-lure backlashes should drop to near zero.
This is the first fix because it solves the root cause. A light lure on light line means the line has almost no aerodynamic drag to slow the spool. Move to a heavier line (up 2 to 4 lb class) for light lures. The heavier line catches more air and creates the drag that slows the spool on the downswing. Counterintuitive, but it is the single biggest improvement you can make for light lures.
If you are running a 3 to 5 lb light lure on 4 lb line, move to 8 to 10 lb line. You are not going to lose the lure's action; the lure is what it is. You are just giving the line more mass to create drag. The trade-off is slightly less casting distance, which you get back in the next fix.
With the heavier line in place, tighten the spool tension knob (the star drag on most reels, or the spool tensioner on others) until you hear three to four ticks on the backswing, then silence. This stops the spool from free-wheeling on the downswing. The heavier line plus tighter tension is the combination that makes light lures castable on a baitcaster.
Lift the rod to the top of the backswing and hold. The spool should tick three to four times, then stop. If it ticks more than five times, open the tension one more click. If it does not tick at all, tighten one click. The goal is not zero ticks; it is a controlled stop.
If your reel has a centrifugal brake, switch to it for light lures. The centrifugal brake only engages when the spool is turning fast. That means it gives you more control during the fast, spool-over-revving downswing that light lures cause, and less resistance during the slow backswing. A magnetic brake applies constant force, which fights the light lure's slow backswing and makes the cast feel heavy.
Start at three detents on a centrifugal brake and cast. If you still get backlashes, add one detent. If the cast feels too short and heavy, back off one detent. The right setting is where the spool turns freely on the backswing and slows down on the downswing, without stopping the cast.
Light lures have less momentum than heavy ones. The spool turns faster relative to the lure's speed, so you need to release the line earlier in the downswing. Instead of waiting for the lure to pass 45 to 50 degrees past vertical, release at 30 to 35 degrees. The earlier release gives the line more time to spool down before the lure hits the water, which reduces the spool over-revving.
When you release earlier, the line has more distance to travel before the lure stops. That extra distance lets the spool slow down naturally instead of being stopped abruptly by the lure hitting water. The abrupt stop is what causes the spool to over-rev and the line to pile up.