Gatling active users drops to negative for a longer run after timeout exception - gatling

Question

I'm running a simulation using gatling.
5 users per second for 150 mins.
After a certain exception:
15:58:19.643 [WARN ] i.g.h.e.GatlingHttpListener - Request 'facebook_outbound_msg' failed for user 29989
javax.net.ssl.SSLException: handshake timed out
at io.netty.handler.ssl.SslHandler.handshake(...)(Unknown Source)
15:58:19.643 [ERROR] i.g.h.e.r.DefaultStatsProcessor - Request 'facebook_outbound_msg' failed for user 29989: j.n.s.SSLException: handshake timed out
15:58:19.643 [ERROR] i.g.h.c.i.DefaultHttpClient - Failed to install SslHandler
15:58:19.678 [WARN ] i.g.h.e.GatlingHttpListener - Request 'facebook_inbound_msg' failed for user 29984
javax.net.ssl.SSLException: handshake timed out
at io.netty.handler.ssl.SslHandler.handshake(...)(Unknown Source)
15:58:19.678 [ERROR] i.g.h.e.r.DefaultStatsProcessor - Request 'facebook_inbound_msg' failed for user 29984: j.n.s.SSLException: handshake timed out
the number of active users dropped to -1, then everytime this exception happens, the number of users keeps dropping.
Example:
---- FacebookOutboundSimulation ------------------------------------------------
[############################################ ] 59%
waiting: 18061 / active: -3 / done: 26942
---- FacebookInboundMessageSimulation ------------------------------------------
[############################################ ] 59%
waiting: 18061 / active: -3 / done: 26942
================================================================================
Why does this happen and how to fix this?

Answer 1

The issue was with gatling-charts-highcharts-bundle-3.0.0-RC1 when I switched to gatling-charts-highcharts-bundle-3.0.0-RC3 that was released on 2nd October 2018 it got resolved.
Sidenote: Use AsJson instead of AsJSON.