There is a possible issue if you are utilizing C-more that any C-more STRING TAG defined MUST have the CORRECT MATCHING Max Length between Designer and C-more. So if the Max Length of the actual string in the PLC is 256 characters, then the TAG definition in C-more better be ASCII (TEXT) with a Field Width of 256 characters (not the default 40).
Double check ALL your string Tags in C-more (SS, SL, LastError block, system heap item strings, user string blocks, user heap items).