Well mIRC simply doesn't retain records of what files were played between instances of mIRC and I can't reproduce this here. Can you replicate this in a clean install of mIRC using /splay alone or does it only occur within that script?
If it's only within that script, have you checked it hasn't alias'ed /splay? And have you tried unloading any DLLs to ensure they're not doing anything?
Also I don't get what you mean when you say it's a "global" script - or is that just the name of it?
The version of Windows you're using would be helpful too.
