Yet are they not both (the Indian Orthodox and the Syriac Orthodox) in communion with the rest of the OO churches? I know that we in the Coptic Orthodox Church recognize both, though which one is mentioned in any given liturgy will vary based on who we have with us during a particular service (in the same way that we are not obligated to mention any given Patriarch outside of those with whom we have preexisting mutual agreements to do so, i.e., the Syriac Orthodox and Eritrean Orthodox; as I understand it, the others are mentioned as is befitting in the presence of any Indian, Ethiopian, or Armenian brothers and sisters). I'm not sure if I'm remembering correctly by this point, but I think the same was true with regard to the recently-healed Ethiopian schism, which by its method of resolution has shown that the 'mainstream' Ethiopians (i.e., not those of the 'Synod in Exile') recognize that those who were in schism from them had a point (it was a very politicized situation somewhat similar to ROCOR vs. the Russian Orthodox situation, if that helps any Chalcedonians reading this: a patriarch had been elevated during a period of great political upheaval, and the resulting enthronement was protested by those who felt that this situation had been tainted by the political actors of the day, and that someone else was the rightful patriarch). Maybe such a thing is not possible among the Indians (Lord have mercy!), but either way, it seems that we in the Coptic Orthodox Church at least are hesitant to take sides in administratively-based conflicts (whereas we have definitely done so concerning heresies, as when the RC heresy of the Immaculate Conception re-emerged as a favorite pet heresy of some in one of the Ethiopian parishes in the USA a few years ago, which led to the local Coptic Orthodox bishop of whichever diocese this was in stepping in at the congregation's own request to provide correction to both the laity and the errant leader! Oof!).
These sorts of things have happened over time, of course. The Syriac Orthodox and the Armenians were in schism over some of the Armenians' unique eucharistic practices for a few centuries, if I recall correctly (this is the context in which Mor Dionysius Bar Salibi wrote his infamous Against the Armenians), and less lengthy periods of estrangement existed for some time between the Copts and the Syriacs (see Lucas Van Rompay's work on Mor Severus in the Greek, Syriac, and Coptic traditions in the Journal of the Canadian Society for Syriac Studies Vol. 8, 2008), and surely others. Please correct me if I'm wrong, my friend, but it is my understanding that the current schism between the Indian Orthodox and the Syriac Orthodox in India arose sometime in the last five decades or so, so it has been within the span of a normal human lifetime, even if its antecedents may obviously stretch back some time longer. We pray that it not continue, and that the parties be reconciled to one another, whether it results in a dual-patriarch situation (like the Ethiopians now have) or in some other arrangement. Again, Lord have mercy.