Interesting.. It can't open it because the revision number in the file is greater than 250. The .lyt format says to not read it if greater than 250, which LYTe checks for.. It seems patch Y saves the files with revision 251.
I don't know what the difference is but it seems to open fine when testing.. I will have to ask Scawen what has changed to see what I can do.
Thanks for letting me know!