If a chain of repeaters set to 1 redstone tick is powered by a 1 redstone tick clock, the last repeater in the chain gets stuck in the powered state. This also happens if all repeaters are set to 2, 3 or 4 ticks respectively.
This behaviour does not occur if the repeaters are separated by a block or piece of redstone dust.
This unintuitive behaviour can be observed in every release version since Minecraft 1.8 (but was not an issue before then)
Edit: I'm sorry but I just noticed this is a duplicate of MC-54711