Error/Warning messages (w0008) attempting to merge subprojects

Hello everyone,
I am trying to analyze a large project by splitting my imagery into 2 subprojects and then merge together after running initial processing separately for both subprojects (computer could not handle all images at once). I keep getting this warning, w0008, saying my camera ID is not found. for enlightenment, i am trying to merge two nadir flights in an agricultural landscape from the same location (main project split in half) on the same flight using multispectral imagery ( Green, Blue, NIR and Red Edge).

I have fully analyzed all three steps in both projects and have had no luck merging them that way either. If anyone has any insight or knows what this error message means, it would be much appreciated.