Traceability of design artifacts is key to software maintainability, yet little empirical evidence exists on UML model evolution in long existing FOSS projects. We refreshed a 2017 dataset—comprising 251 class diagrams across 81 projects—with 735 diagrams from December 2024. Despite a nearly three‐fold increase in raw diagram count, our concept‐tracing analysis found virtually no substantive maintenance: early results show most diagrams remained unchanged or experienced only cosmetic updates. Only one diagram update corresponded to a security design proposal. These findings suggest UML dormancy, highlighting a disconnect between model intent and practice in FOSS.