It is possible for user firmware to affect the cloud connection, by using all available memory, corrupting memory, or failing to give the cloud connection enough processing time.
One way to rule that out is to run minimal firmware like tinker, or this project that is designed to troubleshoot Wi-Fi issues:
Another thing you can try is upgrading to 0.8.0-rc.10. There are some known issues in 0.7.0 that may affect the stability of the cloud connection that are fixed in 0.8.0.