Lulu Ultimate Glitched

Lulu Ultimate won't work on an affected target from her previously cast ultimate. Meaning if the particle effects from her last ultimate still remain no matter how much damage they have taken since it was cast if it is cast on that target again, no knock up and no health increase. Her ultimate targets the lowest health allies, essentially meaning if the target is buffed initially while at 80% health and then they try to ulti it when at 10% health it won't go off if particles are still there. Every single build for lulu suggests trying to make her ulti as often as possible, but that is useless because it doesn't stack when it should.