Nested mixin variable redefinition behavior in LESS 4.x

Goal: Clarify whether a variable redefined inside an inner mixin retains its new value after the inner mixin finishes and influences subsequent invocations of the outer mixin in LESS 4.x.

Context: LESS 4.x follows lexical scoping for nested mixins, but it is unclear if a variable reassigned in the inner scope leaks outward or persists across calls, especially when build tools cache compiled mixins.

Uncertainty: The interaction between lexical scope, variable reassignment, and mixin caching may produce inconsistent CSS output for low‑traffic sites that rely on incremental recompilation.

Specific questions:

• Does the variable keep the inner‑mixin value for later outer‑mixin calls?
• Is the variable automatically reset to its original outer value after the inner mixin returns?
• How might less‑loader or similar caching mechanisms mask or expose this behavior?