Identify Root Cause of Assembly Issue

We are experiencing a recurring issue with one of our assembly processes and have not yet identified the root cause. The process consists of pressing a glass lens onto a plastic housing before encapsulation. The glass has several locating pins that must pass through corresponding holes in the housing. A pneumatic (or hydraulic) press uses a positioning piston/tool to center the assembly and apply downward force on the glass. Once fully seated, the pins should protrude through the housing and lock the glass in its final position before the encapsulation material (OX) cures. The problem is that the locating pins are no longer protruding consistently. On some assemblies, one or more pins do not fully extend through the housing, even though the process appears to complete normally. We have already investigated several possible causes, but we have not been able to identify the root cause. At this point, we are looking for an experienced manufacturing/process/tooling engineer who can review the assembly process, inspect the tooling and press, observe the operation, and help us determine why the pins are not consistently seating correctly. We are looking for someone with experience in: Precision assembly processes Press tooling and fixtures Mechanical tolerance analysis Root cause investigation Potting/encapsulation processes (preferred) The goal is to identify the root cause and recommend corrective actions to make the process robust and repeatable.