Collaborator bitbucket server - endless loop in bitbucket API on pull request

I think there is a bug in Collaborator regarding integration with bitbucket server.

Sometimes there is no review created on pull request. I checked out Collaborator logs and it seems that collaboratior is in endless loop of calling bitbuckets rest API methods.

In bitbucket you can have data splited in pages

    {
        "size": 3,
        "limit": 3,
        "isLastPage": false,
        "values": [
            { /* result 0 */ },
            { /* result 1 */ },
            { /* result 2 */ }
        ],
        "start": 0,
        "filter": null,
        "nextPageStart": 3
    }

Important are fields: start, size, nextPageStart and isLastPage.

Bitbucket on last page is returning

    {
        "size": 3,
        "start": 0,
        "nextPageStart": null
    }

and i think Collborator is taking that nextPageStart null value as 0 and begins calling pages all over again in endless loop.

Bitbucket server version tested is 6.10