ejabberd on azure's memory increased to "61G" - (only Ping)

Hello. I install ejabberd on azure. The version is 15.10 release.(Download at ejabberd github.)
I test it by 60000 Client login (at almost same time try...)... But suddenly memory grow up to - over 60G. My config is almost default.
Is there any issue ejabberd with azure or ejabbberd 15.10 memory issue??