Now, here's some more interesting notes... I was able to replicate losing time-track of my "celestial bodies" the other day, in v0.80. However, that was while testing a Balao, but for other things. I have come back into the game before, after days on patrol, several sinkings, etc., and have had this. I did a wipe of the Save folder though, to clear the data, and I have not been able to replicate it since, using your methodology FrontRunner. I've now tried several submarines besides the Balao. Here is a shot from a Tambor, done on June 3 / 4 1943:
I have a dual-monitor set-up, so the right screen is the screen grab from the 3rd, the left screen is the restored Save of same, after many re-loads of it and other Saves. Part of the problem of course, is the "rock" of the boat. I have not lost my waypoints, though I do remember getting that before, but I do not recall the mod(s) used then. I do not know if I would have lost waypoints the other day when my celestial bodies went "off-the-clock", since I don't often use waypoints, and I don't recall having any set then anyway. I have lost track of how many times I've tried FotRSUv0.80. I have done FOTRSv1.3 at least a half-dozen times, and have not found any issues. I'm still wanting to do Stock and FOTRSv2.0 in SH4 v1.4, and see what happens there. I do not recall which version of FOTRS we took the scene.dat and other files from... I'll ask around about that.
