Copying command blocks placed on the ground wont run the command if placed next to a power source, or if its option "Always Active" is enabled. This also occurs for repeating command blocks. Doing the same for chain command blocks (always active) next to a repeating command block activated by a lever simply crashes the game, and disables the repeating command block from running (even with a lever) upon entering the world again. The command will only be run if the player disables and enables the always active option (if it wasn't enabled just enable it), or activates another power source on another side of it.