Is pre-cooked beef that's not completely dehydrated safe to leave out? Recently, I pan-fried a beef tenderloin (grass fed) till it was medium rare. Then, after slicing it into chunks and marinating it for two hours, I dehydrated it for five hours. After dehydration, the insides of some chunks were still soft, slightly like a very well-done steak, not like dried out jerky—though the outsides of all chunks were thoroughly dry.

Is leaving the soft chunks out in a sealed bag likely safe, or are they a big risk of foodborne illness? They'll be consumed within a week or two.

Here's a picture for reference:
It's probably not safe because your beef isn't fully dehydrated. Chunks don't dehydrate very quickly, which is why they are still soft in the middle - there's still moisture in there. Next time slice it thinly.