GoLand very slow to to symbol search and compilation error detection

I was using trial/beta version in June and it felt faster. I recently purchased the GoLand. It has good features but is so slow at times. Particularly, it will start showing red lines as being syntax errors. Say for example I defined a function and had a return type and now even if I add a proper return value, the red mark takes many minutes to even detect that there is no compilation error any more. At times, I have to restart the IDE. It is very annoying as sometimes I just waste time thinking what is the correct syntax even if there is no syntax error. How do I fix it? I am running - 
GoLand 2018.2.2
Build #GO-182.4129.57, built on August 23, 2018
JRE: 1.8.0_152-release-1248-b8 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Linux 4.15.0-33-generic