You're not alone. I thought it was me, too. Like you, as to why or when, I have no idea. I'm using a mouse. I click-hold one Event List item, and suddenly it seems to select another -- usually below, not above the item I'm attempting to adjust. It skims like a stone on a pond. Thankfully, it doesn't happen often, about once or twice a session..
6-core Mac Mini 2018 with 64 GB and OS 11.3 running Logic 10.6.2, 8-core Mac Pro 2.8 (early 2008) with 16 GB RAM and OS 10.14.1 running Logic 10.4.3, Mac Mini Server mid-2011, Logic Control, Vienna Ensemble Pro (VI and Synchron), Vienna MIR, Ivory