Minecraft wiki entry for Command_Block, associated text: A repeat command block, when it is activated, after 1 game tick (always 1 no matter how many "Delay in Ticks" is), checks whether the command block behind it has executed successfully (if in conditional mode). If the condition is met, and if "Execute on First Tick‌" is enabled in Bedrock Edition, it executes its command once and triggers the chain command block it is pointing to. If it is still activated, it then checks, executes, and triggers the chain command block again after 1 game tick (or more‌[BE only]).