It just looks like the petroleum was pumped out, so the only thing left was the heavy oil. (Notice the pump stops right as the icons change?) Not a bug, however I do agree the visuals are misleading.

The decider combinator that outputs a red signal (input Green) does not output a red signal when set to "input count", but it does output when set to output "1" (when the conditions are true for both.)
The logic adds the 2 uranium types in the chest into a Green variable, and the decider combinator ...