We have identified an issue that affects the Destination Namespace settings for a connection when the connection is toggle (on/off) on the 'Connection' list page.
If a connection with Destination Namespace set to ‘Custom format’, is then toggled (enabled/disabled) from the ‘Connections’ list page, the Destination Namespace will be set from ‘Custom format’ to ‘Mirror source structure’.
We apologies for the inconvenience and we are actively working towards a fix.