inserting pages to a (large) pdf hangs

it's been like this since v11.0.23 on Win 10 pro and it remains the same now that I'm upgraded to 2023.008.20470 on Win 11 pro...

when I try to insert a smaller pdf (a few hundred KB) into a larger one (a few MB), acrobat hangs probably 3 out of 5 times I try. Once it hangs it just never comes back with any errmsg. Only thing to do is to kill the process. And retrying won't make a difference. 

Is there a way to make file insert work for larger files? is it a known issue it doesn't for larger files? I mean 6MB like the one I'm working with now does not seem very large to me. 

thanks