Bug or not in advanced config

In advanced Config i add a type of instance :
:network_performance: :low_to_moderate
:name: m6g.8xlarge
:memory_gb: 128.0
:memory: 137438953472
:intel_aes_ni: true
:instance_store_volumes: 0
:instance_store_size_gb: 0.0
:instance_store_size: 0
:family: General purpose
:enhanced_networking: true
:ebs_optimized_available: true
:ebs_only: true
:description: M6g Octuple Extra Instance
:current_version: true
:current_generation: true
- :arm
:vpc_only: false
- :hvm
:vcpu: 32
When i search In the Flavor menu i can find it, but when i want create an instance with this new type i can’t find this type in the list box !

i missed something ?
Thanks Bruno