compgen not displaying all expected suggestions - bash

Question

I need to add some bash shell completion with words read from a json file:
...
{
'bundle': 'R20_B1002_ORDERSB1_FROMB1',
'version':'0.1',
'envs': ['DEV','QUAL','PREPROD2'],
},
{
'bundle': 'R201_QA069_ETIQETTENS_FROMSAP',
'version': '0.1',
'envs': ['DEV','QUAL','QUAL2','PREPROD'],
}
...
To get a words list I can run this command line and it returns all expected words from my file :
grep 'bundle' liste_routes.py | sed "s/'bundle': '//" | sed "s/',//" | grep -v '#'
for instance, with an addtional "grep R20" it returns :
R20_B1002_ORDERSB1_FROMB1
R201_QA069_ETIQETTENS_FROMSAP
R202_LOG287_LIVRAISONSORTANTE_FROMLSP
R203_PP052_FULLSTOCKSAP_FROMSAP
R204_CO062_PRIXTRANSF_FROMOLGA
R206_LOG419_NOMENCLBOMPROD_FROMTDX
R207_CERTIFNFGAZ
R208_SAL363_ARTICLEPRICING_FROMSAP
R209_LOG451_WHSCON_FROMTDX
Now I put this in this compgen file and source it i my bash session.
_find_routenames()
{
search="$cur"
grep 'bundle' liste_routes.py | sed "s/'bundle': '//" | sed "s/',//" | sed "s/\r//g" | grep -v '#' | awk '{$1=$1;print}'
}
_esbdeploy_completions()
{
#local IFS=$'\n'
COMPREPLY=()
cur="${COMP_WORDS[COMP_CWORD]}"
cur="${COMP_WORDS[1]}"
COMPREPLY=( $( compgen -W "$(_find_routenames)" -- "$cur" ) )
##### COMPREPLY=($(compgen -W "$(grep 'bundle' liste_routes.py | sed \"s/'bundle': '//\" | sed \"s/',//\" | grep -v '#')" -- "${COMP_WORDS}"))
}
complete -F _esbdeploy_completions d.py
complete -F _esbdeploy_completions deploy_karaf_v4.py
complete -F _esbdeploy_completions show.py
The problem is when I type
./d.py R20<TAB>
I get thoses suggestions :
R201_QA069_ETIQETTENS_FROMSAP R203_PP052_FULLSTOCKSAP_FROMSAP R206_LOG419_NOMENCLBOMPROD_FROMTDX R208_SAL363_ARTICLEPRICING_FROMSAP
R202_LOG287_LIVRAISONSORTANTE_FROMLSP R204_CO062_PRIXTRANSF_FROMOLGA R207_CERTIFNFGAZ R209_LOG451_WHSCON_FROMTDX
It misses R20_B1002_ORDERSB1_FROMB1 from my first grep test.
I don't think it deals with the underscore , as other tests with "./d.py R10" do suggests "R10_xxxx".