Redstone Ore stays lit if mined by Silk Touch

I mined some Redstone with a Diamond Silk Touch Pickaxe, so i could use it as Trigger for a BUD

What I expecteted to happen: After placing Redstone Ore, a punch will make it glow for a moment, then it goes off.

What actually happened was: The Redstone stayed lit forever.

To Repoduce:
1. Mine Redstone with Silk Touch or go in Creative Mode and add Redstone Ore
2. Place Redstone Ore
3. Punch Redstone Ore in Survival Mode