Since you prevent ShellExperienceHost preload and jump lists are hosted there, it fails to start on demand when system is out of memory.
Since 1903 you may have different result since SIB does not affect ShellExperienceHost there. Likely you will have jump lists universally broken even without SIB
Can you show a screenshot / screen recording? It's supposed to launch %TEMP%\StartIsBack_update.exe
What is your Windows version?
Are you sure installer is not under some window?
Enable GDI and USER columns, check if there is a resource leak?
Enable 'command line' column, check if it's main shell or separate browsers leaking?
Try to find any noticeable explorer.exe memory leak scenario?
Memory usage should be sub-100MB.