The above is a section of rooms for nobility that I had some difficulty engraving. As you can see, only the room second from the bottom on the right side is fully engraved and the rest are engraved piecemeal.
What happened is that I would designate the entire room to be detailed for the second time, resulting in the blue engraving designation blinking like usual. Workers would show up and begin to engrave. When one of them completed the tile that they were working on, all designations for detailing in the immediate vicinity were cleared and the workers wandered away. I got that one room detailed by selecting one tile at a time, waiting until it was finished, and then selecting the next one over and over and over.
I tried selecting a room using multiple swathes of designation, designating multiple rooms at the same time to see if all the rooms cleared once a single tile completed, and waiting until the engraver currently working had left the vicinity so I could see if it was somehow related to an individual dwarf.
It doesn't happen with every engraving job in my fortress, but it does happen with every engraving job in that vicinity, including the upper-left rooms that are not nearly as jam-packed full of fun furniture. Any time more than one tile is designated for detailing, they will all clear once a single tile in the vicinity is detailed.
I've had it happen in a few other spots but this is the only one at which it's consistantly reproduceable.
Thoughts?