It really depends on the version of select2 being loaded. Some of the features in older versions are not available in newer versions while there are some features in the newer version that did not exist previously. It all depends on what version each is using.
It could have simply been a conflict with the two plugins loading the same code which would cause a JS error and make them both fail. This can happen if the plugins use a different “handle” for the script, if all plugins use the same handle then it is impossible to load two instances of a script, the fist one that gets enqueued wins.
It could also be the the events plugin has altered their version of select2 in a way that makes it possible to load both libraries because they are not identical.
It’s really hard to say.
