JDK 1.8 (8u201)
IntelliJ Ultimate 2018.3
SonarLint version: v22.214.171.12409
With plugin enabled, IntelliJ IDEA UI becomes laggy, with freeze threadDumps in the logs folder. I have contacted JetBrains support, and they indicated that they have received multiple reports of freezing with SonarLint plugin and suggested I report the issue here.
According to JetBrains support, freezes appear related to file I/O. Antivirus software or putting system under load may exacerbate the issue, making it easier to reproduce.