9520 Server Memory too low Gw 18.1.1 Sles 15 SP1

Recently deployed a new SLES 15 SP1 box for Webaccess, running 18.1.1.

For the last few weeks, every week we seem to be getting an 9520 Server Memory too Low error. 
Restarting tomcat fixes it for a short while.

Is this issue addressed in 18.2.1? I know we had this same issue in GW 2014/ Sles 11SP3 and there were some suggestions to edit the tomcat file, (which seemed to fix our issue then)  but not sure if it applies to Sles 15,and  this version of GW - and if so what tomcat file needs to be modified?