Lets assume there is no rain damage or electronic issue for now.

If that's the case, after ten (10) minutes in a half open position, it looks like the top cover action is suspended and needs to be re-initialized.

Here's the sequence write-up, straight from the owners manual:

Top operation can be suspended for a max of 10 minutes. 30 seconds before you reach max, an audible beep will sound, and hydraulic pressure will be released.

In order for the Top to re-initialize the tonneau cover must first be moved and held in its full open position manually.

The Top then needs to be manually lowered and the tonneau top fully closed.

The hydraulic pressure can ONLY be re-established by turning the ignition key to ON/RUN and pushing down the convertibile top switch twice.