Currently playing with this and World Wonders Pack 256 and I am happy to report that it seems to be saving just fine up to turn 136.
Previously failed to save at around turn 50 with Community Patch v89 + Community Patch Mod Compatibility and at around turn 100 with The Dawn of Mankind (BNW) v3 + More Luxuries.

Exactly the same problem as spin. My Civ V is the BNW version, my OS is Windows 10 64 . The problem is maybe indeed at turn 136

A lot of very small mods, nothing else

City limits
Colored religions
Faster aircraft animations
Missionaries do not ignore borders
Unlocked social policies
Krakatoa fix
Pikmen into musketmen

And, of course a civilization ( never 2 in the same time ) like the Amazons

I have some hint on what may cause the problem. For this mod I used a function utility that I did not use previously. In short, I needed to save some data for when the player closes and reloads the game, and this utility (table saver/loader) allows me to do that (edit: like for example if the player uses the Hippomache to capture horses then closes the game, I need to save the number of trapped horses linked to that specific unit, so when the player restarts the game the utility loads the number that was saved and the player can place the resource). I saw other modders used the utility for some of their civs but I did not know it could have bugs.

I will check if without it the issue persists. To do so I have to rewrite part of the code. I found a workaround that is equally effective.
I will test it and if everything works I will update a new version of the mod.

Thank you very much! I am currently playing again, with mods More Luxuries V.155 + Resource Buildings v 3 and it's not saving again. It seems to be linked to the first time you use the capture horse ability (I went back to a save *before* using the Hippomache). Additionally, do you know if this mod and your Samnites mod cause less More Luxìuries to spawn? When I play with either I seem to find less extra luxuries (except for Glass as CS luxury) on the map, but I haven't played enough games to judge if it's like rolling six times a 1 on a common die or if it's a weighed die.