pg-promise: ERROR TypeError: Cannot read property 'options' of undefined

I got errors like logs below. I see it’s my failure that conections are over limit. The issue is next to the error.

I’m not sure but it should be cnOptions instead of options ?

(snip)
{ error: remaining connection slots are reserved for non-replication superuser connections
   at Connection.parseE (/usr/src/app/node_modules/pg/lib/connection.js:567:11)
   at Connection.parseMessage (/usr/src/app/node_modules/pg/lib/connection.js:391:17)
   at TLSSocket.<anonymous> (/usr/src/app/node_modules/pg/lib/connection.js:129:22)
   at emitOne (events.js:96:13)
   at TLSSocket.emit (events.js:191:7)
   at readableAddChunk (_stream_readable.js:178:18)
   at TLSSocket.Readable.push (_stream_readable.js:136:10)
   at TLSWrap.onread (net.js:561:20)
(snip)
 [Fri Sep 08 2017 01:44:03 GMT+0000 (UTC)] ERROR TypeError: Cannot read property 'options' of undefined
   at BoundPool.onError (/usr/src/app/node_modules/pg-promise/lib/database.js:1320:25)
   at emitTwo (events.js:106:13)
   at BoundPool.emit (events.js:194:7)
(snip)