I am having a problem with Lr keeping my edit changes. I was at a family wedding and shot 1,100 and am trying to make a relatively quick 1st edit pass. Particularly, I am working on reception shots, in a very dimly lit room, with many bright, white, small lights. With this and white dresses, I want to adjust Highlights to -100, Shadows to +100, and generally Whites to -100 and raise Exposure. (I could further adjust on a shot by shot basis.)
I have tried selecting 100's of shots at a time and then in Develop make those changes with Auto Sync. I have also made the changes to one photo and then Control-Shift-C to copy and then select 100's of shots at a time and then Control-Shift-V to paste the settings. When I then look at the sequential shots, the first few get the changes, but many do not, and I do it over again. When I get to a photo that the changes did not take, I see the failed changes in History, but they are NOT reflected in the Exposure block.
One possibility is that it will take Lightroom a few minutes (depending on your hardware) to update all of the images, your computer is doing a lot of work.
"Time" it does take!
Another method might be to set your initial parameter changes (Highlights to -100, Shadows to +100, and generally Whites to -100 and raise Exposure) on one image and then create a Develop Preset that specifies these Basic panel adjustments.
Next- in the Library Grid view, select all the photos you wish to adjust (100's), and select the Preset in the Quick Develop panel. You will watch and see the changes as each thumbnail gets the adjustments applied.
eg. The Preset Drop-down menu in Quick Develop-