Command blocks do not update themselves after being triggered. When a command block is powered by a redstone block, it changes its trigger value from false to true. But, when the redstone block is removed, the trigger value remains as true until the command block is updated. This can be seen in the attached screenshots from the debug HUD.
MC-61846
Command blocks do not update trigger value
Resolved
Fixed
1
(Unassigned)
Unconfirmed
Minecraft 14w28a, Minecraft 14w28b, Minecraft 14w31a
Minecraft 1.8
Retrieved
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.