Falling through the earth?

Im playing as player2 with my husband as host i will be out hunting resources and the like wgen reguardless of how close i am in proportion to his toon i will fall through the earth unable to maintain standing on land and will begin swimming under the landscape. Typically this is followed by me being forced to respawn in an endless loop where i spawn in the desert and just fall again and again at which point i have to turn off and unplug my Xbox resulting my toon losing all gear and resources collected thus far exceedingly frustrating