Shib IdP V3.2.1, Jetty 9.3.6, and HTTP/2

[Tom Scavo]

I'm working with a colleague at Williams College to register metadata
for a v3.2.1 IdP deployment. Just beneath the surface of this IdP,
there is some weirdness going on. We believe we can trace it to Jetty
9.3.6 but first let me provide the symptoms.

The URL that exhibits the problem is an old V2 Status URL:

https://idp.williams.edu/idp/profile/Status

Shib IdP V3.2.1 should return 404 on such a request, and for some
browser clients (such as Chrome) that is exactly what happens. Other
browser clients are all over the map.

Curl on my Mac produces this:

$ curl --verbose https://idp.williams.edu/idp/profile/Status
*   Trying 137.165.4.25..
* Connected to idp.williams.edu (137.165.4.25) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
* Server certificate: idp.williams.edu
* Server certificate: COMODO RSA Organization Validation Secure Server CA
* Server certificate: COMODO RSA Certification Authority
* Server certificate: AddTrust External CA Root
> GET /idp/profile/Status HTTP/1.1
> Host: idp.williams.edu
> User-Agent: curl/7.43.0
> Accept: */*
>
* Connection #0 to host idp.williams.edu left intact
invalid_preface

Other curls on other client machines produce different results but
none of them 404.

We've googled and experimented and have come up short. Evidence is
pointing to Jetty and its handling of HTTP/2 but we can't be sure.

Has anyone else seen anything like this? Other suggestions?

Thanks in advance,

Tom