Whatsapp flows Not Working (JSON is Invalid)

hello team, I am unable to publish or preview Flows form. If i preview or try to publish Flow shows this error. i checked on different waba ac both have same error means this is issue from BS side. Link to error image - https://bot-data.s3.ap-southeast-1.wasabisys.com/tickets/31600/flows.png

I found a bug or limitation as below in Screen Unique Name if i add numeric it throws an error. only text works properly. so please mention in hint use only text. thanks

Yes i see, thanks