Tableview crashes on toggleSection method.

Fatal Exception: NSInternalInconsistencyException
0  CoreFoundation                 0x191d981c0 __exceptionPreprocess
1  libobjc.A.dylib                0x1907d055c objc_exception_throw
2  CoreFoundation                 0x191d98094 +[NSException raise:format:]
3  Foundation                     0x19282282c -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:]
4  UIKit                          0x197f0bf78 __46-[UITableView _updateWithItems:updateSupport:]_block_invoke.996
5  UIKit                          0x197c0ed78 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:]
6  UIKit                          0x197c25b84 +[UIView(UIViewAnimationWithBlocks) animateWithDuration:delay:options:animations:completion:]
7  UIKit                          0x197dd81c0 -[UITableView _updateWithItems:updateSupport:]
8  UIKit                          0x197dbc6a4 -[UITableView _endCellAnimationsWithContext:]
9  Kim Beach                      0x10008f454 -[FZAccordionTableView toggleSection:withHeaderView:] (FZAccordionTableView.m:335)
10 Kim Beach                      0x10008ee84 -[FZAccordionTableView tappedHeaderView:] (FZAccordionTableView.m:262)
11 Kim Beach                      0x10008e3b8 -[FZAccordionTableViewHeaderView touchedHeaderView:] (FZAccordionTableView.m:69)
12 UIKit                          0x1981a7a2c -[UIGestureRecognizerTarget _sendActionWithGestureRecognizer:]
13 UIKit                          0x1981ab134 _UIGestureRecognizerSendTargetActions
14 UIKit                          0x197d6c804 _UIGestureRecognizerSendActions
15 UIKit                          0x197c0ad44 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:]
16 UIKit                          0x19819b178 _UIGestureEnvironmentUpdate
17 UIKit                          0x19819acd8 -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:]
18 UIKit                          0x198199f94 -[UIGestureEnvironment _updateGesturesForEvent:window:]
19 UIKit                          0x197c08f60 -[UIWindow sendEvent:]
20 UIKit                          0x197bd9a44 -[UIApplication sendEvent:]
21 UIKit                          0x1983c6ea8 __dispatchPreprocessedEventFromEventQueue
22 UIKit                          0x1983c0910 __handleEventQueue
23 CoreFoundation                 0x191d46278 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
24 CoreFoundation                 0x191d45bc0 __CFRunLoopDoSources0
25 CoreFoundation                 0x191d437c0 __CFRunLoopRun
26 CoreFoundation                 0x191c72048 CFRunLoopRunSpecific
27 GraphicsServices               0x1936f5198 GSEventRunModal
28 UIKit                          0x197c44818 -[UIApplication _run]
29 UIKit                          0x197c3f550 UIApplicationMain
30 Kim Beach                      0x10009453c main (AppDelegate.swift:19)
31 (Missing)                      0x190c545b8 (Missing)

Start by reproducing the header toggle and inspect FZAccordionTableView.m at toggleSection:withHeaderView: (line 335), then follow tappedHeaderView: (line 262) and touchedHeaderView: (line 69). Use the reported UITableView assertion as the completion criterion and confirm that section toggling no longer crashes.