WARNING: This page is about a different car, the 2020 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
When removing the back trim from the seat back crossmember assembly, clip B installation holes may be damaged causing the noise due to loose fit of clips B.
Courtesy of MAZDA MOTORS CORP.
Clean and degrease around clip B installation holes of the seat back crossmember assembly.
Courtesy of MAZDA MOTORS CORP.
Attach the fabric sheet to the clip B installation holes of the seat back crossmember assembly as shown in the figure.