Follow up PD units

Quote from Ryan26

When I send police units to a follow up mission and send them directly to it they return to their patrol route rather than going to the call but will respond to other calls that they are not followed up on until the previous call they were on is completed. It's really annoying.

You had me confused with this one for around 10 minutes and I'm not even sure quite why.
I've tested sending units to follow up calls while on patrol and this seems to work fine.

However I suspect that's not what this one is about.
Below I have tried to rewrite what you've written but still can't see any sense at the moment:
So you assign a a patrol car that is patrolling to call 1, you also assign to call 2 as a follow up, but until call 1 is completed it won't respond to call 2 but will be able respond to calls 3/4/5 and goes back to patrolling.

Could you provide some screenshots of what you're doing, may help greatly.