The short-side/long-side connector pattern looks wrong

Stop and verify the duct piece and shop detail. Typical slip-and-drive uses slips/S on one pair of sides and drives on the other, but transitions and fittings can make the pattern look different.

Make the metal fit right before sealing, insulating, or moving on. S-and-drive problems usually come from alignment, seating, support, damage, or wrong connector pattern.

Rectangular Duct & Fittings 2nd Year YELLOW

Stop if

Ask when the pattern is different from the rest of the run or the piece may be rotated/wrong.

Watch out

Do not use force, screws, tape, or mastic to hide a bad mechanical fit.

Check

Confirm piece mark, size, airflow, and connector sides
Seat the S and drive cleanly
Check corners, support, gaps, and sharp edges

Steps

Identify the long sides and short sides.
Match connector to fabricated edge type.
Check piece mark and next fitting.
Dry-fit before sealing.
Ask if it does not match the shop drawing.

Say this to your foreman

In Rectangular Duct Assembly: S-and-Drive, I'm looking at: The short-side/long-side connector pattern looks wrong. What should I verify before I cut, drill, seal, cover, move, or install?