I am not sure this is a a real bug or just a graphical glitch.
While patching I changed input of Frac (value) from one output to another and was surprised when vvvv did not delete the old connection. see attached image. I made a screen shot before saving and of course the glitch disappeared before that I tried copying the part of the patch to a new patch and the glitch did not copy to the new patch.
I can not reproduce the bug… not even in the same patch.
double_input_bug.jpg (7.6 kB)