I noticed this when converting the Lemmings Plus packs, and from the #neolemmix chat logs I see Flopsy has encountered this bug too. Sometimes, a level that has postview text but not preview text, will end up having the postview text changed to a preview text.
I haven't looked in-depth enough to find where the issue lies; the only part of the chain that can be definitely ruled out are the player itself and (for obvious reasons) the graphic set tool. I don't think it's with the Flexi Toolkit, as I've opened and closed packs, and even modified final-level talismans, without the issue resurfacing - but I could be wrong, especially if it's an "only happens sometimes" issue.
It could be the conversion tool (in which case: conversion tool doesn't compile properly under Delphi XE6 and if I'm not mistaken Nepster is not particularly familiar with its workings, and at any rate the tool will not be needed for too much longer; so my suggestion would simply be to draw attention to this issue so pack developers know to look out for and correct it). Or, it could be the level editor - the last time I encountered this bug, it *was* on a level I had modified in NLEditor. (Note for readers not too familiar with internal workings: In new-formats, preview / postview texts are stored as part of the level file, so while the level editor doesn't edit them in any way, it does have to at least know how to preserve them; a bug in this could very well be the cause.)
