I remember seeing some speculation by others that alien ASIs may tend to befriend each other and ally together as opposed to fighting.

It does seem to be in both their best interests. At least it appears that way to a non-ASI like myself. They can mutually benefit from trade if necessary, but risk losing a lot in a destructive war. It would also be easy to tell when the other ASI is preparing to attack since space is so empty and you can get a line of sight from anywhere. It also takes foreeeeever to travel, so there's not much element of surprise (ignoring any possible FTL travel).