[Win] ASSERTION FAILED: m_wrapper in WebCore::JSEventListener::ensureJSFunction

WinCairo Debug MiniBrowser (262385@main) is reporting an
assertion failure just by loading
https://www.prusa3d.com/product/original-prusa-mk4-2/ now.

ASSERTION FAILED: m_wrapper
C:\home\webkit\gc\Source\WebCore\bindings\js\JSEventListener.h(163) : WebCore::JSEventListener::ensureJSFunction
1   00007FFA7B3F249B WTFCrash
2   00007FF9D9821F7E WTFCrashWithInfo
3   00007FF9DBAA7259 WebCore::JSEventListener::ensureJSFunction
4   00007FF9DBAA164A WebCore::JSEventListener::handleEvent
5   00007FF9DC3464A1 WebCore::EventTarget::innerInvokeEventListeners
6   00007FF9DC345DE4 WebCore::EventTarget::fireEventListeners
7   00007FF9DC34B807 WebCore::EventContext::handleLocalEvents
8   00007FF9DC34D512 WebCore::dispatchEventInDOM
9   00007FF9DC34CD55 WebCore::EventDispatcher::dispatchEvent
10  00007FF9DC3C736E WebCore::Node::dispatchEvent
11  00007FF9DC7CB300 WebCore::HTMLScriptElement::dispatchLoadEvent
12  00007FF9DC416E4A WebCore::ScriptElement::dispatchLoadEventRespectingUserGestureIndicator
13  00007FF9DC4165BD WebCore::ScriptElement::executeScriptAndDispatchEvent
14  00007FF9DC4158C1 WebCore::ScriptElement::executePendingScript
15  00007FF9DC451AE2 WebCore::ScriptRunner::timerFired
16  00007FF9DC4604FE std::invoke<void (__cdecl WebCore::ScriptRunner::*&)(void),WebCore::ScriptRunner * &>
17  00007FF9DC459B3E std::_Invoker_ret<std::_Unforced>::_Call<void (__cdecl WebCore::ScriptRunner::*&)(void),WebCore::ScriptRunner * &>
18  00007FF9DC459BBB std::_Call_binder<std::_Unforced,0,void (__cdecl WebCore::ScriptRunner::*)(void),std::tuple<WebCore::ScriptRunner *>,std::tuple<> >
19  00007FF9DC4597BB std::_Binder<std::_Unforced,void (__cdecl WebCore::ScriptRunner::*&)(void),WebCore::ScriptRunner *>::operator()<>
20  00007FF9DC467A8B WTF::Detail::CallableWrapper<std::_Binder<std::_Unforced,void (__cdecl WebCore::ScriptRunner::*&)(void),WebCore::ScriptRunner *>,void>::call
21  00007FF9D9895F84 WTF::Function<void __cdecl(void)>::operator()
22  00007FF9DB44187B WebCore::Timer::fired
23  00007FF9DD29C7E8 WebCore::ThreadTimers::sharedTimerFiredInternal
24  00007FF9DD29E14F `WebCore::ThreadTimers::setSharedTimer'::`8'::<lambda_1>::operator()
25  00007FF9DD29E72B WTF::Detail::CallableWrapper<`WebCore::ThreadTimers::setSharedTimer'::`8'::<lambda_1>,void>::call
26  00007FF9D9895F84 WTF::Function<void __cdecl(void)>::operator()
27  00007FF9DD23BDD7 WebCore::MainThreadSharedTimer::fired
28  00007FF9D99EEC1A WebCore::TimerWindowWndProc
29  00007FFAF2CDE7E8 CallWindowProcW
30  00007FFAF2CDE229 DispatchMessageW
31  00007FFA7B5826D6 WTF::RunLoop::run
Exception thrown at 0x00007FFA7B3F24A0 (WTF.dll) in WebKitWebProcess.exe: 0xC0000005: Access violation writing location 0x00000000BBADBEEF.