I've not had that but had a similar issue when calling kameos cancelling into special moves. And it changes depending on tje combo.
For example, using sindel with sektor. When I call the rocket in a certain combo, f1 will not cancel into a special move no matter how much I try. So I have to use 24 string instead.
And then another combo, when I call sektor rocket, 24 string will not cancel into a special, so I have to use f1 instead...
Very strange how it's not consistently the same strings that don't let me cancel, or even all of them, and that it changes depending on the combo. Makes doing them on the fly quite confusing.