The issue here appears to be having URL in the Link text. Current implementation of CIL does encode link text but since we have URL, it needs double encoding so that CIS can handle the request.
As a workaround, this link text can be encoded before passing it to the API. As a result, the response will contain encoded link text which needs to be decoded again.
Ref: https://docs.oracle.com/javase/8/docs/api/java/net/URLEncoder.html
As another workaround, can you try adding below JVM args when starting content service ? This can be done by adding this to $jvmoptions section in start.ps1 which can be used to start the service.
-Dorg.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true -Dorg.apache.catalina.connector.CoyoteAdapter.ALLOW_BACKSLASH=true