This ended this particular colony, and happened more than once. It occurs when I destroy large sections of floor tile and tried to replace them with either mesh or gaseous exchange tiles. In the screen shot all tiles are set to priority 9 with no other tasks. Earlier, I had dupes standing idle next the the blocks, stressed out because they couldn't move. The materials were delivered and the status said construction pending.
In all cases, there was nothing I could do to get the dupes to build the tiles even though they were walking over the area and had the resources to do so.
Steps to Reproduce
destroy ordinary tiles and replace with mesh or gaseous membrane tiles
This issue has not been confirmed by a developer yet.