Corrupt Save Files WobsterDen workleft #QNAN

Dear Klei Devs,
we decided to rollback for a day after a wildfire cought part of our base on day 333+
I am using some mods on this server but until now even with some rollbacks everything always worked fine.

After the last rollback our save files seem corrupted. The return string for GetPersistentString() is truncated in the server log and therefore the error code -1 is returned instead. This happened with all saves from 362 to 359 so far which I then removed (making a backup before) from the save session folder. Now I only got 358 and 357 left to try and I'm scared that those will be corrupted as well.
When I open those corrupted save files notepad++ though, they seem to be normal null terminated strings.

Is there any chance to fix this or at least to revert the world back into a previous playsessions state and avoid this corruption?
Or is there just too much information on this world (has a custom size huge) and a corruption of a savefile in a modded world is in inevitable past a certain date?

My playgroup invested quite some hours into this world so far and we would be really sad if we have to start completely from scratch again.

I am including a copy of the server log with the crash trying to load save file 359, as well as the whole Cluster folder of my Overworld and Cave server parts including the broken save files I already tried to exclude and my server launcher.
Is there anything else that would help?

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Edit:
So apparently I found and fixed the bug.
Somehow a wobster_den ended up in a state with an illegal 'workleft' value given as workleft=1.#QNAN  so  Not_A_Number instead of an integer.
I think I got an idea what might have caused this. After a server reboot my boat bridge to lunar island for which I had not used anchors was all over the place and one of the boats was glitched under a wobster den and flickering positions. That was very annoying so I put a bit of grass on there, took a fire staff and set the flickering boat ablaze. This might have triggered the illegal wobster den workleft value.

After setting it manually back to a legal integer (i tried 9 which i found in TUNING.lua) the save file is loaded properly again.

I also tried to set it manually to 1 and it was indeed the particular wobster_den which took fire damage from the glitched boat burning underneath it. When workleft was set to 1, it was destroyed after one swing with a golden pickaxe.

server_log.txt Cluster_3_Overworld.rar launch_preconfigured_servers3.bat Cluster_3_Caves.rar