So, I originally posted this under Moosh's NPC script, but he suggests that this might actually be a 2.55 bug. I'm on 2.55 alpha 92 build 57. On this screen, I'm using his NPC script and his GB Dungeon cliff script. Codes are the following:
What happens is, on this particular screen, once the message is displayed, Link can still move freely about:
I double checked that the quest rule "Messages freeze all action" is enabled, and it is. I setup another screen with both scripts and there is no problem, the screen freezes:
However, I went to this next screen, the only script there is the GB dungeon cliff and the bug is the same, upon displaying the item string, Link moves freely about:
I don't recall this behavior on Alpha 85, (I can't seem to find a download link to alpha 85 to try this out in it), but I'm sure this began on Alpha 92...
Let me know if you need any more details.