In Creative Mode, in Sealantians Reef Rescue. I have already contacted developer, who says this is a Minecraft issue!  After digging a few pits, about 4 blocks deep, to place selected mobs for showcase, demo purposes, anvils started eating name tags. Anvils also started eating maps. This happened whether items were placed on anvil to rename, or to make copies of an anvil.  This is especially frustrating for renaming and reproducing Explorer Locator Maps, when making a map wall, due to labor intensive, time-comsuming efforts.

This happened previously in the end of adventure area of the World, in a previous session, with a separate 'world', created from the Sealantians template.

Is it possible that I broke some blocks in some type of command-field area, such that the anvils no longer perform as expected?