When include a large Event-B models (>400 lines), TeX capacity exceed. The workaround is to include the model in smaller "bunches"
\EventBinputlisting[firstline=1,lastline=400]{large_model.bumx}
\EventBinputlisting[firstnumber=401, firstline=401,lastline=500]{large_model.bumx}
This should be mentioned in the documentation.
(This is discovered and reported by COMP1216 AY2021-22 students)