web application – Is this HSTS HTTP Response Header Misconfigured?

I recently discovered during a penetration test that the HSTS was returned by the application but in this format:

“Strict-TransportSecurity”

Instead of:

“Strict-Transport-Security”

Does this format mean that the header (HSTS) is not validated by the client and prevented from doing what it is designed to do? As I understand HTTP headers are case insensitive but I’m not sure if this is a valid header name.

Any advice is greatly appreciated. Thank you