I have deployed sling:OsgiConfig and its working fine but when I change the same in felix console its converting to nt:file.
All the string properties are changed to key/value paired(i.e. autor.stream5="dsdyttyxxd1234xsds")
But in case of Boolean value its changed as key/value with extra B added(i.e. auth.enabledDisabled=B"true").
Is it correct behaviour?
Yes, If you change repository based config values from Felix console, it would be save in flat file.
If you are using repository based config, you need to change from repository otherwise you'll ended up that.