It is very difficult to work out what is wrong, if you do not include your project.
You certainly can get one or both paths executed as you describe. Have a look at the attached project which demonstrates this.
Import project into your designer, deploy it to your bpms and start from the bpms console. Enter starting messages 1,2,3 to emulate your three options.
The working variable is use to collect data from each task to show the order of execution.
for extra credit :)
use starting message of 4 and explain the result! Nether of Path1 or Path2 are taken but the EitherorBoth step that follow them is taken.
Seriously , you should ensure that all cases are allowed for and I did not allow for values other than 1,2,3. but it is
not a smart feature of designer to allow this.
Further, I think that the final task eitherorboth is actually avaiable to be executed twice in case 3 but the terminate gets there first.
David