Update: my testing and analysis are essentially complete. I have rewritten the description and the mod list field with the results.
In short:
- The failure is caused by the module-wide static initializer budget described in T200535. It is filled by static and static const initializers that construct objects or arrays, according to their size, and it is shared by vanilla and all loaded addons.
- It can be reproduced with vanilla plus one test addon (reproduction A), and with ten public workshop mods (reproduction B).
- On my server the trigger was SHS Modular Framework 1.2.2, whose static routing table grew from 53 to 120 entries. The modpack had no headroom left, and pinning that addon to 1.2.1 fixes it.
- Load order makes no difference, and the number of mods does not matter: a server with about 160 addons starts because its static initializers are smaller in total.
The figures in the description are based on a rough unit of my own (elements of static initializers), not on internal engine values. I will add anything else I find.