Security focus – CVE-2019-1367: Microsoft conducted remedy for CVE-2018-8653, but a item not being fixed. Suspected that this is one of the reason let Microsoft Releases Out-of-Band Security Updates on 23th Sep 2019.
Should you have interested of this matter, please refer to attached diagram. The official announcement can be found at: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1367
Apart from that out of band update also covered Microsoft Defender Denial of Service Vulnerability CVE-2019-1255. Official announcements can be found at: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1255