I just updated to version 3.3.7 of Carpenter's blocks (From version 3.3.6). I had a couple of carpenters safes placed in my base, which I after the update no longer could access.
Furthermore it seems that the Carpenter's safes is unbreakable even for OPs.
All this is server side only. All seems fine in a singleplayer world.
Forge Version: 10.13.4.1448

It would be nice to get all the kinks worked out with Safes at some point. I will test this out thoroughly and do my best to resolve it.

Your recent commit might have fixed/changed the accessing the safe issue. Needs further testing from my side.

But fantastic that you will look into it ^^

Development builds are now being pushed on website. Please let me know if you encounter any more ownership issues.

Works like a charm! Good job @Mineshopper.

I will keep this open, to make sure you see that it works as intended!