The cooldown is not reduced but for some reason the duration is much much shorter despite not being mentioned in the node description. I’m not positive this is caused by the rifts node but it is the only difference between this time and last time I made a black hole build.
Edit: Sorry maybe the duration part is not a bug afterall, I just didnt realize how short the base duration is. The cooldown doesn’t seem to be reduced by the rifts node though. Despite having increased cooldown recovery speed.
What were you doing at the time?
How consistently does this happen?