I was just taking off my propellers from their quick release brackets.  I have never had a problem with them previously but one of my propellers would not come off.  After several tries, by not pressing down all the way I was able to get the final propeller off.  Then I noticed that the bracket was loose.  I got out my allen wrenches and tightened it up.  The bracket was very loose and would eventually have come off.  I also tightened the other brackets but none were loose.  

The warning is clear, be sure your brackets are on tight.  Secondly, I have gone several flights without taking off the propellers, for quite a while.  I think I am going to change that practice now and check the brackets more regularly.  

Has anyone else experienced a loose bracket, where the screws are loose?  I have not heard of this problem and so I was shocked to see it.  

I am glad you caught the issue before anything bad happened. If possible, can you take some pictures to help the community?

Yes, please post some photos when you can.

In flying R/C helicopters, we use thread locker such as blue Loktite on screws to keep them from backing out due to vibration and temperature changes.  Perhaps this would be a good idea for the screws discussed here?  Ordinary tools can remove the screw if needed.  Be sure not to use red thread locker or you will NOT be able to remove the screw without resorting to a blow torch

I had similar issue but I always remove my props after every flight.
Tighten back the screws on the bracket an all good to go.
Just be aware that if you over tighten the screws you may end up with crack on the motor.
Plenty of material to read about here in the Forum.

Not sure what props you guys are talking about but I just received the newly designed quick release props and I really like them. I skipped the second generation as I just never trusted them. I was happy to hear that no one had issues with them. I even had a set but never installed them. For whatever reason I just felt like the newer designed ones were a much better design so I purchased a set. I am happy to report they work perfect but they only have about 30 minutes of flight time on them

Houston