Some objects disappear in main camera

As shown in picture, the foot are OK in scene and 2nd camera, but disappear in main camera, any suggestion?

Do the cameras have the same culling masks?

6640294--757834--upload_2020-12-19_10-54-53.png

It includes every layers, except the other camera layers. The foot are on the “body part” layer.

During game play, the foot appear and disappear randomly. And I don’t have the problem now for unknown reason.