I say that because if you have more than one male, one may be dominated by the other. If it is a female, she can be stressed by the continual pursuit from one or more males. Dwarf gouramis are peaceful towards other species but males can be agressive toward their own. Males are territorial and will chase each other. Males courship females, sometimes agressively. Those 2 comportments, in a tank, may lead to harassment cases. I have seen it often.
I have two maleD's and ive had to lay out the aquarium to give them their own geographical territories to prevent fighting. now if you have one male and three females that would be dandy hehe
domination could def be the culprit