Random SSL wrong version error at https://api6.ipify.org

[slowphil]

When querying https://api6.ipify.org, about one out of 3 of requests end up with SSLError WRONG_VERSION_NUMBER. Here is such instance:

wget https://api6.ipify.org --2021-02-28 18:34:21-- https://api6.ipify.org/ Resolving api6.ipify.org (api6.ipify.org)... 2607:f2d8:4010:c::2, 2607:f2d8:4010:8::2, 2607:f2d8:4010:b::2 Connecting to api6.ipify.org (api6.ipify.org)|2607:f2d8:4010:c::2|:443... connected. GnuTLS: An unexpected TLS packet was received. Unable to establish SSL connection.
As seen above the address api6.ipify.org resolves to 2607:f2d8:4010:c::2, 2607:f2d8:4010:8::2, 2607:f2d8:4010:b::2. The server at address 2607:f2d8:4010:c::2 yields the error, while the other 2 connect correctly and return the answer.

[mdmower]

I'm seeing the same error

$ curl -6 -verbose https://api6.ipify.org
*   Trying 2607:f2d8:1:2d::20:443...
* TCP_NODELAY set
* Connected to api6.ipify.org (2607:f2d8:1:2d::20) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* error:1408F10B:SSL routines:ssl3_get_record:wrong version number
* Closing connection 0
curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number