I hope this clarifies the situation.
Concrete cases are:
1) the text of SRFI 170, which is an MIT-licensed work derived from a BSD-licensed work, and therefore must include a copy of the BSD license, a copy of the MIT license, and SPDX metadata for the MIT license only;
2) the text of SRFI 246, which is an MIT-licensed work derived from a Apache-licensed work, and therefore must include a reference to the Apache license, a copy of the MIT license, and SPDX metadata for the MIT license only.