Matt Kaufmann reported (in Jan, 2026) a problem with books/quicklisp/fastnumio.lisp when ACL2 is built on Allegro CL 10.1. The output included the following:

Include-raw Warning: compiled file failed to load; loading uncompiled /books/quicklisp/fastnumio-raw.lsp
Details: V1 Failure: beef --> spec "beef" !== impl "BEEF"

We don't plan to pursue this further unless someone requests it.