Specifically, we employed operando SEM microelectrode methods while controlling the contact force between the microprobe and LLZO surface. Combining these statistics with electrochemical modeling, we found that the intrusion probability as a function of lithium metal diameter follows a Weibull distribution, suggesting a defect-driven intrusion initiation mechanism. We observed that a high mechanical loading (5 mN vs. 0.1 mN) dramatically increases the likelihood of intrusion events, causing more intrusions at smaller electrode diameters. A combination of ex situ indentation measurements and finite element method (FEM) simulations suggests that nanoscale cracks likely initiate intrusion in LLZO. Furthermore, operando LLZO cantilever bending experiments revealed a strong mechanical strain effect on regulating the propagation of intrusions. Our work establishes a method to quantify the effects of microstructural defects and mechanical strain on solid-state electrolytes and motivates the use of advanced characterization to further understand nanoscale defects in these complex systems.