trap on EXIT doesn't get triggered in functions run in background

[Tau]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
-Wno-parentheses -Wno-format-security uname output: Linux
fedora31.localdomain 5.3.11-300.fc31.x86_64 #1 SMP Tue Nov 12 19:08:07
UTC 2019 x86_64 x86_64 x86_64 GNU/Linux Machine Type:
x86_64-redhat-linux-gnu

Bash Version: 5.0
Patch Level: 7
Release Status: release

Description:
        When you execute a function in the background, and in that
        function you set a trap on EXIT, it doesn't get triggered when
        the function returns. This behavior doesn't seem to be
        documented anywhere and other shells (zsh, dash, ash) behave
        differently.

Repeat-By:
        The following script should print:
        done 1
        done 2
        cleanup

        #!/bin/sh
        
        cleanup() {
            wait
            echo cleanup
        }
        
        do_work() {
            sleep 2
            echo done "$@"
        }
        
        run() {
            trap cleanup EXIT
            do_work 1 &
            do_work 2 &
        
            # It does work with explicit exit
            #exit
        }
        
        run&