[Koha] Koha accountlines issue_id equals "zero"

Hi all! Koha 17.05.09.000 Debian 8, I'm seeing a lot of issue_id with data equals to "0" (zero) in the accountlines table in one Koha ILS installation. It must have been an error? The correct issue_id is not being recorded in the accountlines table. I'm seeing like 9,712 out of 24,000+. What could be the reason that instead of the correct issued_id recorded in the accountlines.issue_id is recorded instead 0 is being recorded into that column? Any thoughts? -- Sent from: http://koha.1045719.n5.nabble.com/Koha-general-f3047918.html