I have 18A Victron Orion Smart DC-DC charger in Campervan. It doesn’t seem to be charging to Leisure Battery at all. I can see on the app it has output of 12v on the AGM Spiral battery settings. I checked the connections to both batteries and these are OK. Have I set something incorrect to push charge into the LB?
Orion has automatic on/off logic that's based on the incoming voltage. This needs to be set carefully and may not work depending on the cable voltage drop. It also has a connector to turn the unit on and off.
Need more info on your setup:
wiring diagram with cable sizes and lengths
current Orion programming
Input and output voltage readings
The Orion is on a 2.5m cable run from starter battery and 0.5m to LB from Orion. Both 16mm cable.
Settings as below. 
I’m going to pull it out and have it tested by supplier.
