I should also have noted that an LOI is a Letter o

I should also have noted that an LOI is a Letter of Intent. That's very different from an MOU (Memorandum of Understanding). All an LOI is is an expression of an intention to reach agreement. Because legal documents become invalid if they're no statements about duration, this LOI had a stop date. This didn't change the intention of the parties to keep intending, so to speak. The evidence being ... it took some months and they reached an agreement.