Yes, sure.
If I use one hot encoding for targets, then there is no such error because the length of the vector is same.
But if i drop this encoding and just use image labels as such, for example:
Image Number   1,     Label: (0, 4)
Image Number   2,    Label: (1, 3, 4)
Image Number   3,    Label: (1, 5, 7, 8)
Then the error appears.
Thanks