I may have found something but I cannot be sure as replication is extremely hard to do - its not a rare occurrence, and its not a script incompatibility. But when I try to replicate it its odd.
The window size is as follows: 308x78 (WxH) the text lines max is set to two both in the script config and in the script you use in the event box to set up a talking npc.
paragraph formatting is on.
Sometimes, if I have more then 2 lines of text, even if i dont, the words get cut off.
"Sally mary had a log, dog on a frog" will some times be "Sally mary had a log, dog on a fr"
I say sometimes because usually talking to the again fixes this issue and the text aligns fine. Is this my issue, or your issue? Again replicating this is really hard as it doesn't ALWAYS happen while sometimes it does