At some point after the Airport scenes, the game saves can no longer be re-loaded. This has happened to me in a number of places, e.g. The History Museum and on the train.
On one run, I have tracked the saves step-by-step and attached the following examples at the History Museum scenario : sword25.010 (the towel is on the mud - this will reload) and sword25.011 (having entered the building - this will not reload) .
Language : English
Windows 7 Ultimate 64-bit
It would be nice to fix it before the release of 1.8.0. Raising priority.
This should be fixed now by https://github.com/scummvm/scummvm/pull/659