Followed the instructions in Take a map offline—ArcGIS Pro | ArcGIS Desktop to set up a feature service for offline editing. Add it to a new map, but didn't download the map. Select by Attributes works great. Download the map (take the FS offline), and select by Attributes no longer works. Same expression as when I did it against the online FS. Validate won't even work. Just those 5 dots marching across the screen, over and over again. I looked through the documentation, and didn't see anything about some functionality being disabled when a feature services is taken offline (and it's now coming from a SQLite DB). But, perhaps the case, and I'm missing it in the documentation? (because that makes sense, SQLite limits what you can do with the data). I get the same result in Pro 2.1.1/Win 10, Pro 2.1.2/Win 10, and Pro 2.1.2/Win 7.
