Similar issues have been posted several times, one of the main threads here:
https://community.hubitat.com/t/2-2-4-139-woke-up-to-slowwwww-world-delays-non-responsive/55901
Signs seem to point to something in 2.2.4.x causing the issue... some of us have reverted back to 2.2.3.148 (last 2.2.3.x release) which has resolved this specific issue, with the obvious downside of lost functions from the 2.2.4.x releases.