People start putting more stuff inside tabpages without realizing the limit of possibilities.
If the QT is a non ajax QT then you can throw mostly anything into it.
You can create a block, which is a panel, which contains ten nodes and some views. You can create a node which contains three views. You can use these stuff without problem inside non ajax QTs, because they are all loaded at page load, quicktabs does not interfere with their rendering, it just simply hides some of it when someone clicks on the tab.
So what could be insibe ajax QT?
The confusing thing is that there is one exception: you can put ajax view inside ajax QT, but that is only because it got special care from the quicktabs module. That means if you select view as a tab type then it should work. You can use views pagination and filtering, even you put it into ajax QT. But you can't use a block or node which contains the ajax view, because that won't work. The view must be directly under the tabpage.
So if you can't select the ajax view directly as a tab then you must turn off ajax rendering for the QT.
It is not enough? You really need to put more ajax stuff inside ajax QT. I don't know. I did not tried pushing these limits. But you may experiment and report back what worked for you. I know there is a thing in views, called attachment display which could display additional view inside view, but I must tell I never tried that with QT.
So if you know other secrets about how special ajax things can be inserted into ajax QT, then you can share it here.