I can't open the back hatch of my 2002 Hyundai santa fe what's wrong?

My 2002 has the same problem at varying times. Sometimes I could just cycle the master lock/unlock. Today, though unlocked, it would not open.

My campground was especially dusty this weekend, and as I leave the hatch open to keep the sun off of my coolers and help the airflow keep the temp in the vehicle lower, I decided to "blast" the handle area with a high pressure water stream from the hose thinking that may help clear out any gunk inside. It worked!

I'll get some spray lube that will allow the stem to be inserted in/behind the operating handle to see how long the good effects last.