Yaml keys starting with number are being double quoted when mapper.writeValue()

I am writing a YAML file with mapper.writeValue() but the keys that start with a number are being double quoted even if the original key doesn't have the quotes.
I understand that the double quotes are being added because mapper want to avoid YAML to consider a String as a number, but it would be better for me to avoid the quotes.
I've tried with enable(YAMLGenerator.Feature.MINIMIZE_QUOTES)) but not helping with this issue.

Example:
//original key -> after writeValue()
6712dd2a-2695-49cb-89a8-9b5592951522: -> "6712dd2a-2695-49cb-89a8-9b5592951522":