Crushed flex is an airflow restriction, not a finish-detail inconvenience. Pull it out of the pinch point and use an approved rigid/alternate path that fits the wall cavity without choking the branch.
Do not leave flex flattened in a wall cavity because it is hidden.
Check
Confirm where the flex is being pinched and whether drywall/framing is already installed.
Check branch size, diffuser/boot location, and whether rigid wall stack/oval/rectangular duct is specified or approved.
Check for access to replace the crushed section before the wall closes.
Look for excess flex length, tight bends, and strap/crush damage.
Take a photo of the pinch and ask before changing material or route.
Steps
Confirm where the flex is being pinched and whether drywall/framing is already installed.
Check branch size, diffuser/boot location, and whether rigid wall stack/oval/rectangular duct is specified or approved.
Check for access to replace the crushed section before the wall closes.
Look for excess flex length, tight bends, and strap/crush damage.
Take a photo of the pinch and ask before changing material or route.
Say this to your foreman
The flex branch at [location] is being crushed by framing/drywall. I checked the boot and wall cavity. Do you want a rigid wall-stack/oval replacement, a reroute, or a different boot location before they close it?