If I may, I want not to report a bug but a solution. I am running SH5 TWoS on:
1. Windows 10, i5 4670k @3.4Ghz, 8GB RAM DDR3 2133Mhz, Nvidia GeForce 960.
2. Silent Hunter 5 disc version patched and registered on Uplay afterwards.
3. 1.2, and was running without the mod.
I still noticed the game being slightly unstable especially if fulfilling a mission or when a lot of activity was on the screen. So I started using the 4GB RAM Patcher again. This is basically a free tool that updates the Exes of 32bit programs so they are able to use up to 4GB of RAM. Usually 32bit programs are not able to do so because 800MB were reserved for the OS. So if you use this tool, the game is able to use additional 800MB of RAM. According to the experience of at least two friends and myself this greatly increases stability especially close to the coast, when finishing missions and during really big convoy attacks.
THIS WILL ONLY WORK IF YOU ARE ACTUALLY RUNNING THIS GAME ON A 64BIT OS WITH MORE THAN 4GB OF RAM!
I recommend this tool here:
https://ntcore.com/?page_id=371
Simply download, start the tool up, select the Sh5.exe, done. That's it. By the way, this works with every older game that is rather RAM hungry.
Enjoy!