In PCB DFM process; manufacturer have highlighted Gullwing Issue. What is Gullwing?
Gull Wing packages are a kind of package lead configurations as can be seen below.
The GullWing package is depictured in image (a). If there is a problem with the DFM process regarding Gull Wings, I would suggest looking at the component and see if the datasheet recommend a landing pattern / solder mask layout and see if your design is compatible with that. It might be that the way it is designed now will not lead to an optimal solder joint and therefor reliability.



Image from: Reflow Soldering Processes and Troubleshooting: SMT, BGA, CSP, and Flip Chip Technologies by Ning-Cheng Lee