As per @MSchoenmakers-Signify mention of the bug, the workaround that I'm using is as follows:
On Library Load, I'm updating the s.t() function.
var tempTrack = s.t.bind({});
s.t = function(e,t,justInCaseParam,justInCaseParam2){
tempTrack(e,t,justInCaseParam,justInCaseParam2);
someOtherPostBeaconCode();
}
Seems to be sufficient to just add on to the existing track function, but played it safe, in case new parameters are added to the s.t() function in the future. Similar code can be replicated for s.tl() as well.