I have a set of fluid transposers attached to a lightwell from Astral Sorcery. After some time, they will simply be gone, and fluid transfer will halt.
I've tested a few things; the disappearance isn't caused by the lightwell's crystal breaking, and it doesn't seem to happen when chunks unload or anything like that. I can't see any reason for it, but it will happen consistently after some amount of time. I've had them last for a very long time (5~ hours) and some that will break in less than an hour.
The translocators are not dropped as items when this happens.

Edit: This also happens with item transposers. :/

I think this is actually related to chunk unloading, please show me a screenshot of your setup with the chunk overlay on.

https://i.imgur.com/tlITHVO.jpg
tank is from evilcraft

Can confirm this issue while playing FTB Continuum

So, this might be an FMP issue, does closing and opening the world make them 'reappear'?

No, but sometimes they disappear after re-opening the world.

I am having the same problem, and it is reproducible in some cases.

In this spot, every time I place translocators, log out and back in, they disappear.

These are the logs from just logging in adding the translocators and relogging:
debug.log.gz
latest.log.gz

Here is the chunk overlay.

Translocators placed to go to the chest above the storage drawer also disappeared, but the one to the left never has. I have gotten it with vanilla chests only as well.

Another translocator that has never disappeared.

I have tried some in another world and have not been able to reproduce it.

Interesting, can i get your entire instance? World, mods, config, Feel free to poke it to me on discord if you don't want to post it here.

Sure, how do I do that. It's ~400MB with the mods (my own pack).

Edit: I emailed you a link to dropbox.

I suggest Google Drive or Dropbox.

are you 100% sure that after they disappear, reloading the world does not make them reappear? If that is the case, then this is a far deeper issue..

Actually, can i get a full log file, from a launch where the parts were removed please?

I can' t reproduce it now, need some time to figure out.

Yeh, I'm also having the same issue on FTB Continuum

I'm currently in the middle of a play through of FTB Continuum, i haven't come across this yet, but its easier to debug in the wild, i will check out tsurezuregusa pack the provided some time next week.

Cleaning this in to a single issue: TheCBProject/CBMultipart#29

Hello,
I have the same issue in the Foolcraft 3 modpack. They just disappear....
Greetings