Why does it draw black squares (libgdx)?

Question

libgdx

If the application is closed (with the back button) and reopened, some sprites are drawn with a black square.
It seems obvious that the problem is that the texture is not loaded, or forgot to call dispose on it and the like. But! Some objects are drawn correctly, and some are drawn with a black square, although they are all mapped from the same texture. And all the alpha channel is used. Those. it is not at all clear why one sprite is drawn, and instead of the second, a black square. If the application is unloaded through the "applications2" menu, then the next time everything is displayed correctly.
I can't give the code, it's too much...