'06 GLS -- Trunk Only Opens with Key/Remote Combo

[lothian]

'06 GLS
141k miles

Prior to the date of this post, there were zero issues with opening the trunk. Now, however, the lid will not open when...

• the driver's door truck release is pulled (solenoid is heard);
• when the remote button is pushed (solenoid is heard);
• the key is turned within the trunk lock.

Two things do open the trunk: Emergency Release within the trunk, and doing the "turn-trunk-key-in-lock-then-press-remote-button" trick, a fact that confounds me.

Anyone have experience t'shooting this problem?