Merged project 1st step results disappearing

Hi, I’m running Pix4dmapper 4.10.0. I need to merge two projects, one is with rgb images, one has thermographic .tiff files.

The projects seem to merge fine and I can see the tie points and in the 3d view after the merging. As soon as I open the processing options and change any setting before starting the step 2 or 3 (even if I don’t change any setting at all) and I press ok, the 1st step greys out and I can’t process step 2 or 3. If I close and reopen the merged project, the tie points disappeared and the 3d view is empty. If I press x rather than ok in the processing option, nothing happens and I am allowed to run step 2 and 3.

I need to change my processing settings as I want to produce a thermographic model, so I want to use the rgb photos to generate the geometry and the thermal photos for texturising.

I can’t re-run the 1st step in the merged project as it will mess up my alignment and several photos, especially the thermal ones become uncalibrated. So I’m stuck.

I tried two different PCs and I get the same behaviour.

Can anyone help please?