It happened to me too this morning. I was disappointed, because the "leeching sliver" card doesn't say "other slivers have:..." but only he himself activates his own ability. I was at 13 life. My opponent casts leeching sliver and writes "good game", then attacks. After declaring attackers, when the creatures attacked, 4 activations of the leeching sliver ability appeared. Only, instead of doing 1 damage for each creature, it did a "machine gun" of 4 damage for each attacking creature. So I took 16 damage, went to -3 and stayed looking at the phone for a minute trying to understand what had happened... it's a 100% bug, there's no doubt about it.
It happened to me too this morning. I was disappointed, because the "leeching sliver" card doesn't say "other slivers have:..." but only he himself activates his own ability. I was at 13 life. My opponent casts leeching sliver and writes "good game", then attacks. After declaring attackers, when the creatures attacked, 4 activations of the leeching sliver ability appeared. Only, instead of doing 1 damage for each creature, it did a "machine gun" of 4 damage for each attacking creature. So I took 16 damage, went to -3 and stayed looking at the phone for a minute trying to understand what had happened... it's a 100% bug, there's no doubt about it.