No content to map to Object due to end of input

[Nitzan Mass-Ader]

I'm getting the following RestClientException 400 when trying to update an issue via the SDK. My deps:

<dependency>
    <groupId>com.atlassian.jira</groupId>
    <artifactId>jira-rest-java-client-core</artifactId>
    <version>6.0.2</version>
</dependency>

The error response:
[ErrorCollection{status=400, errors={}, errorMessages=[No content to map to Object due to end of input]}]

The request payload (after being formatted by the SDK from the IssueInput object):

{

"fields": {

"summary": "<REDACTED>",

"issuetype": {

"id": "10010"

},

"project": {

"key": "AIT2"

},

"description": "<REDACTED>",

"priority": {

"name": "Medium"

},

"labels": [

"<REDACTED>",

"<REDACTED>"

]

},

"properties": []

}

This problem is only recreated when working against a company-managed project which I do not have admin access, if that helps narrow it down. Team-managed projects work fine.

Things I've tried:

1. Updating the library to version 7.x.x, but this seems to require Java 21 and I am developing for 17.
2. Running the request through postman, seems to work fine with the same Authorization data, URL, params and headers.
3. I tried debugging the error, I have a hunch it's something to do with the response parsing of whatever is returned. As far as the v2 API is concerned, the request should return 204 with no content, but I also tried it with the returnIssue set to true and I get the same response.

Any help will be appreciated as this seems to be either a simple request structure problem for most people, or the question is left unanswered.