Fix.

Author: WaVEV

django_mongodb_backend/functions.py

@@ -252,9 +252,9 @@ def trunc_convert_value(self, value, expression, connection):
     return _trunc_convert_value(self, value, expression, connection)
 
 
-def trunc_date(self, compiler, connection, **extra):  # noqa: ARG001
+def trunc_date(self, compiler, connection):
     # Cast to date rather than truncate to date.
-    lhs_mql = process_lhs(self, compiler, connection)
+    lhs_mql = process_lhs(self, compiler, connection, as_path=False)
     tzname = self.get_tzname()
     if tzname and tzname != "UTC":
         raise NotSupportedError(f"TruncDate with tzinfo ({tzname}) isn't supported on MongoDB.")
@@ -320,7 +320,7 @@ def register_functions():
     Substr.as_mql_expr = substr
     Trim.as_mql_expr = trim("trim")
     TruncBase.as_mql_expr = trunc
-    TruncBase.convert_value_expr = trunc_convert_value
+    TruncBase.convert_value = trunc_convert_value
     TruncDate.as_mql_expr = trunc_date
     TruncTime.as_mql_expr = trunc_time
     Upper.as_mql_expr = preserve_null("toUpper")