Hi and thanks for your question and great pictures of your dropping immature Douglas fir cones. Doug firs sometimes dump immature or unpollinated cones in summer, either because of a prolonged drought or extensive insect damage.

I don't see any sign of insect damage but there definitely might be some squirrel participation unless you took that cone apart in the picture. If so, it is probably drought related. We are recommending people water even their native Douglas firs these days, a good long soak every couple of weeks to help them cope with the raising temperatures.

And in case there is a squirrel issue, there are some interesting facts on the following website about what you can do.
https://solvepestproblems.oregonstate.edu/rodents-wildlife/squirrels