Why does normalizing a smart object render video inoperable

Hi

I am using PS CC 2019 on windows,  I am editing a video that needs to be straightened, having read that the resizing and straightening should be done only once and not again afterward it would make sense that this should be the last step and that all other edits should be done prior to making it a smart object because the client could ask for multiple formats for different occasions.  I have two video clips running back to back, they both require some masks and adjustment layers (preferably before they are made smart objects) so before I put the time in, I wanted to be sure this will work in the order I want.  I have worked ahead of myself without doing the other edits and I find that going to Layers>Smart Object> rasterize does normalize (is that right) the layers but I lose the video logo in the layer thumbnail and the video seems to now be a still.  What am I doing Wrong?

Hope I have explained this clearly, thanks

Chris