fix: handle cyclic u0map in some cases

Author: AayushSabharwal

src/systems/problem_utils.jl

@@ -596,10 +596,14 @@ function build_operating_point!(sys::AbstractSystem,
     end
 
     for k in keys(u0map)
-        u0map[k] = fixpoint_sub(u0map[k], neithermap)
+        v = fixpoint_sub(u0map[k], neithermap)
+        isequal(k, v) && continue
+        u0map[k] = v
     end
     for k in keys(pmap)
-        pmap[k] = fixpoint_sub(pmap[k], neithermap)
+        v = fixpoint_sub(pmap[k], neithermap)
+        isequal(k, v) && continue
+        pmap[k] = v
     end
 
     return op, missing_unknowns, missing_pars
@@ -785,11 +789,11 @@ function process_SciMLProblem(
     else
         obs, _ = unhack_observed(observed(sys), Equation[x for x in eqs if x isa Equation])
     end
-    is_time_dependent(sys) || add_observed_equations!(u0map, obs)
 
     op, missing_unknowns, missing_pars = build_operating_point!(sys,
         u0map, pmap, defs, cmap, dvs, ps)
 
+    add_observed_equations!(u0map, obs)
     if u0_constructor === identity && u0Type <: StaticArray
         u0_constructor = vals -> SymbolicUtils.Code.create_array(
             u0Type, eltype(vals), Val(1), Val(length(vals)), vals...)
@@ -811,7 +815,7 @@ function process_SciMLProblem(
         op[iv] = t
     end
 
-    is_time_dependent(sys) && add_observed_equations!(op, obs)
+    add_observed_equations!(op, obs)
     add_parameter_dependencies!(sys, op)
 
     if warn_cyclic_dependency