You're using the MQSC Adapter to send messages to an MQ server. Intermittently, the messages do not make it to their destination. But the corresponding send port instances are still in an active/running state.
This issue occurs because the MQSC Adapter uses the MQOO_INQUIRED open option. This option does not support sending messages to an alias.
This issue is fixed in Cumulative Update 2 for Host Integration Server 2016.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology Microsoft uses to describe software updates.