EXC_Breakpoint when not forcefully unwrapping

问题

I'm getting a crash EXC_Breakpoint which would indicate to me that there is a nil variable being unwrapped?

The line of code it is pointing to is the definition of let obHeight:

if let qs = Helper_Question.getSection(sid: self.sections[0].sid) {
   let obEnabled = Helper_Type.getId(id: tid)?.enableObservation == 1
   for q in qs {
       let ans = Helper_Answer.getQuestion(aid: selectedAid!, qid: q.Id)
       var baseHeight : CGFloat = 300
       switch(q.qtype){
       case Constants.DEFAULT:
            let obHeight : CGFloat = (obEnabled || ans?.comment != "" || (ans?.answer == "1" && q.hasChildren == 0) || (ans?.answer == "2" && q.hasChildren == 0)) && ans?._na == 0 ? 40 : 0
             ....
        }
    }
}

I'm using the ? instead of forcefully unwrapping so I don't think this is the issue? This crash report came into today but I cannot reproduce it on any device. What other reason apart from a nil variable would cause a EXC_Breakpoint crash? This code is called on action of a button click in a table view cell and uses a delegate to call this code to do some calculations before presenting a splitviewcontroller. selectedAid comes from the button's accessibility identifier which i am setting in the cell for row, always. it is not nil

crash log:

Crashed: com.apple.main-thread
    0  AppName                        0x100664b30 specialized AuditVC.editBtnTapped(cell : PendingAuditTVC) -> () (AuditVC.swift:294)
    1  AppName                        0x10065fa68 AuditVCAppNamePendingAuditCellDelegate (AuditVC.swift)
    2  AppName                        0x100717468 PendingAuditTVC.editTapped(Any) -> () (PendingAuditTVC.swift:41)
    3  AppName                        0x100717648 @objc PendingAuditTVC.editTapped(Any) -> () + 4302730824
    4  UIKit                          0x1907c6010 -[UIApplication sendAction:to:from:forEvent:] + 96
    5  UIKit                          0x1907c5f90 -[UIControl sendAction:to:forEvent:] + 80
    6  UIKit                          0x1907b0504 -[UIControl _sendActionsForEvents:withEvent:] + 440
    7  UIKit                          0x1907c5874 -[UIControl touchesEnded:withEvent:] + 576
    8  UIKit                          0x190d5a550 _UIGestureEnvironmentSortAndSendDelayedTouches + 4280
    9  UIKit                          0x190d5689c _UIGestureEnvironmentUpdate + 1128
    10 UIKit                          0x190d563e0 -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 404
    11 UIKit                          0x190d5568c -[UIGestureEnvironment _updateGesturesForEvent:window:] + 268
    12 UIKit                          0x1907c070c -[UIWindow sendEvent:] + 3164
    13 UIKit                          0x19079133c -[UIApplication sendEvent:] + 340
    14 UIKit                          0x190f8b014 __dispatchPreprocessedEventFromEventQueue + 2400
    15 UIKit                          0x190f85770 __handleEventQueue + 4268
    16 UIKit                          0x190f85b9c __handleHIDEventFetcherDrain + 148
    17 CoreFoundation                 0x18a61542c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
    18 CoreFoundation                 0x18a614d9c __CFRunLoopDoSources0 + 540
    19 CoreFoundation                 0x18a6129a8 __CFRunLoopRun + 744
    20 CoreFoundation                 0x18a542da4 CFRunLoopRunSpecific + 424
    21 GraphicsServices               0x18bfac074 GSEventRunModal + 100
    22 UIKit                          0x1907f6058 UIApplicationMain + 208
    23 AppName                    0x100044590 main (AppDelegate.swift:23)
    24 libdyld.dylib                  0x18955159c start + 4

UPDATE

open class Question
{
    open var Id : Int = 0
    open var sectionid : Int = 0
    open var question : String = ""
    open var hasChildren : Int = 0
    open var qtype : Int = 0
    open var defaultValue : String = ""
}

public class UP_IA_Answer_m : EVObject {

    public var localId : String = ""
    public var aid : String = ""
    public var sid : Int = 0
    public var qid : Int = 0
    public var answer : String = ""
    public var comment : String = ""
    public var hasChildren : Int = 0
    public var _na : Int = 0
}