If you are planning on catching Ivysaur, then do not even think about it. The Grimer bug is now connected to this Pokemon. Some trainers are complaining about the bug that is brought about by loading Ivysaur's 3D model. It is reported that some parts of the game will freeze or might quit working. There are also times that the game will completely stop working once Ivysaur will come out in the game which resulted to users are asking if developers can provide a fix to this problem.
According to Heavy, there is a group of users in Reddit that has found a way to solve the problems related to Ivysaur. The username yuvi3000 led this discovery. It has been discovered that the loading of the 3D model is the primary reason why the game will break, thus all Pokemon will disappear from the map. This then results to the crashing of Pokemon Go. Sometimes it even led to the "white screen of death". The 3D models loading process is also applicable when trainers are checking on in their Pokemon storage or Pokedex, thus it hides the Pokemon in the Pokedex. It is also troubling for some when Pokemon cannot be seen in the wild, in the gyms, or when hatching an egg.
According to Otakukart, this process though can be altered by restarting the game or the phone. However, this solution has not worked for some users, thus they have to clear the cache of their Pokemon Go app, or worse, they have to reinstall the game. There is also a negligible percentage of users that were not affected by the bug at all. Therefore, it would just be better to just avoid catching or even get close to Ivysaur as of the moment. It is best to have it that way, rather than going through all the hassles of re-installing the app and restarting the game.