PR# 16682 Error in flat short when using `across'

Using the `across' loop in a routine and requesting the flat of the routine results in the following flat with the warnings about the routine IDs. The errors are for `c.item' and `c.target_index'.

Is this expected?

	process_std_byte_code (a_node: STD_BYTE_CODE)
			-- Process `a_node'.
		local
			l_real_type: TYPE_A
			l_reg: C_REGISTER
		do
			if attached a_node.arguments as l_args then
				across
					l_args as c
				loop
					l_real_type := real_type (c.item)
					create l_reg.make (l_real_type.c_type)
					l_reg.set_is_argument
					l_reg.set_index (c.target_index)
				end
			end
		end

	-- Error(s) occurred, which was due to a compilation failure.
	-- Feature with routine id 15964 could not be found.
	-- Feature with routine id 15977 could not be found.

I've verified that the routine ID involved there are indeed the routine IDs for `c.item'. So they are valid IDs, it is just that the formatter is not able to display them properly for some reasons.