OFS link broken because of program unit in Unity

I'm merging 2 PLC programs in each other to become one.

I'm using OFS between UNITY and VIJEO CITECT and it's been working fine until I putted the Robot program into my PLC on the next rack.

If i'm deleting the programma unit.  In this case the 2 robots my OFS link is again working, so the problem is the program unit.  We are working with Vijeo Citect 2018 and the OFS that is delivered with it.  Has any some experience with this kind of problem.

Thx Roeland