X64 App in Microsoft Store not working (due to coreclr.dll ? )

Hello Community,

msxibundle x86 is working in App in Microsoft Store.
x64 msxibundle crashes when starting the App, we see the following error in eventviewer.

Faulting application name: SystemTrayMenu.exe, version: 1.0.12.0, time stamp: 0x5ec598f1
Faulting module name: coreclr.dll, version: 4.700.20.26901, time stamp: 0x5ec48a29
Exception code: 0xc0000005
Fault offset: 0x0000000000191d5b
Faulting process id: 0x2468
Faulting application start time: 0x01d668b0c8a8a99e
Faulting application path: C:\Program Files\WindowsApps\49543SystemTrayMenu.SystemTrayMenu_1.0.12.0_x64__y4xj13v8chxp8\SystemTrayMenu\SystemTrayMenu.exe
Faulting module path: C:\Program Files\WindowsApps\49543SystemTrayMenu.SystemTrayMenu_1.0.12.0_x64__y4xj13v8chxp8\SystemTrayMenu\coreclr.dll
Report Id: 4421b053-5319-47b8-b07a-5634e2e45cf3
Faulting package full name: 49543SystemTrayMenu.SystemTrayMenu_1.0.12.0_x64__y4xj13v8chxp8
Faulting package-relative application ID: App

see also here

Thank you in advanced for your help!