MongoDB Connection issue

I want to understand why no. of connections on replica nodes are not uniform here and available connection on one node are very less as compared to other. Please help to understand it . OS resources are same across the cluster

rsplusmetdb:SECONDARY> db.serverStatus().connections
{
“current” : 32344,
“available” : 72513,
“totalCreated” : 2278667,
“active” : 4
}

rsplusmetdb:SECONDARY> db.serverStatus().connections
{
“current” : 23215,
“available” : 376785,
“totalCreated” : 2936577,
“active” : 4
}