Poison Bird Land Blinds

Oaks Area 2

With temps forecast to near 90° with no wind today, I got the dogs out early, while temps were still in 70s, for some work on land.

SERIES A. Double poison bird land blind with mark picked up after first blind (Laddie, then Lumi)

First, I walked out to the left and thru a duck to 30 yards, with a gunshot. Then I ran the dog on the blind 90° to the right at 80 yards. Next, I sent the dog to pick up the duck. Finally, I ran the dog on the blind midway between the previous two retrieves at 150 yards. Both blinds were ODs.

Both dogs lined the short blind on the right despite the PB, and despite the knee-high, prickly cover, both dogs nailed the mark. Both dogs required some handling on the longer blind on the left, but both dogs remained responsive on WSs and casts. Lumi, however, showed the same problem she's shown in the past, of not carrying her casts very far but instead scalloping back on a line she had previously veered to and be cast away from.

This makes me wonder. Why does a dog who's been handling for nearly two years, and who in thousands of handling retrieves has never once been cast in the wrong direction, not yet trust my casts as the most efficient way to get to the blind?

Here's a video made up snapshots showing the three lines for the Series A retrieves: