Wire Link IDs are being reset to "L35" format

Hi All,

In Promise standalone 08.11.11.18, I have one project whose Wire Link ID's continuously get set back to "L" numbers, eg. L35, L50, L64... 

I have just opened a project where I'd spent some time going through the whole project correcting the wire links over week ago. But when I opened each page today, I could see the correct ID's disappear to be replaced with "L" numbers.

Has anyone else encountered this problem?

Regards,

DM