2005 Sonata V6; trunk lid lock

The trunk lid lock on my 2005 Sonata V6 works just fine,
except...
there is a way to disable the "trunk button" on the driver door.
When this disabling works OK, then it is necessary to use the car key
to open the trunk.

To disable the "trunk button" there is a small lever (at the trunk
lock) that is pushed up to accomplish the disabling.
This worked fine for me for several months but now when I try to do it,
I find that the small lever is rigid and cannot be moved to accomplish
the disabling.

All comments will be appreciated,
Thanks

 

And the vehicle is not still under warranty? I'd say it's an easy fix.

 

Yes, it is still under warranty.
But it would be nice to hear from someone who has faced this "minor
problem".

Besides, my next visit to the dealer will not occur for a few months,
when I go for an oil/filter change.

Cheers...