Content-Length missing from header

Hi!

I have been facing a strange issue, since last thursday. When I make a HEAD request for a file stored on my server there is no Content-Length field in the response header in case the file has .bin extension. Otherwise if the file has .exe extension the Content-Length field is present.

Nothing has been changed or updated on the server, nor on my Cloudflare account since then by myself.

Any ideas?