This partially reverts https://www.openstreetmap.org/changeset/154039485.

OsmAnd apparently has a bug that messes up nodes of a building when modifying its tags and uploading the changes. When I initially tried to upload changes in the mentioned changeset, I encountered a network error that prevented the upload. After logging back in with my OSM account, this time using the OAuth method, the changes uploaded successfully into the said changeset.

iD editor displayed the building with its nodes shown even when it's not selected, but it didn't throw any warnings or errors.
On the other hand, the JOSM validator complained of "Duplicate way nodes" and "Way contains segment twice", despite the area having the same exact number of nodes.

I solved this by doing the following:

0. In JOSM preferences, check the Revert Changeset and utilsplugin2 plugins if they are not installed.
1. Find the changeset that caused the building to appear invisible
2. Open the area in JOSM where the problematic building is located, then select the building
3. Go to Data > Revert Changeset, then enter the changeset ID, and select "Revert selection only" and "Download as new layer"
4. Copy the same building in the "Reverted Changeset" layer
5. Switch to the original layer, select the building, and move it anywhere from its original position
6. Paste the reverted building using Edit > Paste at source position (Ctrl+Alt+V)
7. Select both buildings, then go to More Tools > Replace Geometry (Ctrl+Shift+G)
8. Select the newly merged building and run the validator (Shift+V) to ensure that no errors were generated

It would be nice for anyone in the OsmAnd development team to take a look at this and address it so that this never happens again.