Pulling painted sheetrock off metal studs

Hi folks, After heavy rains recently, we noticed that the ceiling in the upstairs bathroom has a tiny leak. The small crack (attached image) has been there earlier, just never paid attention to it. The leak was tiny, a very slow drip-drip that later stopped, but I have no idea whether this is a small or big problem. What are the possible reasons for this to happen? Does it necessarily mean a leak in the roof above, or could it be something else? Any suggestions would be much appreciated! Thanks a lot in advance, Agam

Looking for advice on fiber ceiling planks. Armstrong website suggests using adhesive on sound surfaces or their metal track system for less solid surfaces. I want to use regular 1x3 furring strips instead of their metal track system which is rather expensive. The tongue and groove looks like it has a wide stapling flange similar to standard square tiles. Is 16" spacing for my furring strips good? Also, do the butted ends (which are also tongue and groove) need to be supported? My house is old and the ceiling joists are covered with wood and drywall/plaster/fiber tiles. The way i want the planks to run will cause my furring strips to run parallel to the joists, not perpendicular as recomended. The screws that will secure the strips will bite into the wooden boards that make up the first layer of the ceiling. Is this ok? If not, do you have a suggestion how to run them? Diagonally? Lol. Just starting this project so any and all advice is welcome... can't have too much info!