Not worth a second's thought. Very clear that TSA has the authority to search and does so on both a random and targeted basis. Whether your bag was just the unlucky random bag or there was anything from a piece of odd-looking something, a piece of clothing folded so that one part was more dense, a good item, a wire/cable or whatever, is of no consequence.

If you are a regular traveler who still checks luggage, you should expect it regularly.