Portable FASL is not concatenable contrary to documentation in manual

When loading a fasc file obtained by concatenating multiple fasc files using cat, it appears that only the first file is actually loaded:

$ cat repro/1.lisp 
(defun one (x) (+ x x))
$ cat repro/2.lisp 
(defun two (x) (* x x))
$ ecl
> (compile-file "repro/1.lisp")
;;; Compiling repro/1.lisp.
;;; Compiling #<input stream repro/1.lisp 0x7f3fa46e0320>.
#P"repro/1.fasc"
NIL
NIL
> (compile-file "repro/2.lisp")
;;; Compiling repro/2.lisp.
;;; Compiling #<input stream repro/2.lisp 0x7f3fa422f500>.
#P"repro/2.fasc"
NIL
NIL
> ; exiting ECL every time to clear the image
$ ecl
> (load "repro/1.fasc")
;;; Loading "/home/lukas/src/depot/repro/1.fasc"
#P"/home/lukas/src/depot/repro/1.fasc"
> (load "repro/2.fasc")
;;; Loading "/home/lukas/src/depot/repro/2.fasc"
#P"/home/lukas/src/depot/repro/2.fasc"
> (+ (one 1) (two 2))
6
> ; exiting
$ cat repro/1.fasc repro/2.fasc > repro/bundle.fasc
$ ecl
> (load "repro/bundle.fasc")
;;; Loading "/home/lukas/src/depot/repro/bundle.fasc"
#P"/home/lukas/src/depot/repro/bundle.fasc"
> (+ (one 1) (two 2))

Condition of type: UNDEFINED-FUNCTION
The function TWO is undefined.

Available restarts:

1. (RESTART-TOPLEVEL) Go back to Top-Level REPL.

Broken at SI:BYTECODES. [Evaluation of: (+ (ONE 1) (TWO 2))] In: #<process TOP-LEVEL 0x7f11b11a4f80>.
>> (one 1)

2

I would expect the second case to behave like the first case as documented in Section 3.1.1.1 of the manual.

     VERSION "21.2.1"
      VCS-ID "UNKNOWN"
          OS "Linux"
  OS-VERSION "5.10.52"
MACHINE-TYPE "x86_64"
    FEATURES (:WALKER :ECL-BYTECMP :CDR-1 :CDR-5 :LINUX :FORMATTER :CDR-7 :ECL-WEAK-HASH :LITTLE-ENDIAN :ECL-READ-WRITE-LOCK :LONG-LONG :UINT64-T :UINT32-T :UINT16-T :COMPLEX-FLOAT :LONG-FLOAT ...)