I have a repeatable crash that I'd like to see if it happens to others and I have another issue which is becoming a problem...

First the crash. This happens usually after a few minutes into the game and may be responsible for a lot of the "5-15 minute" threads.
Have a number of different items, let's say 10, preferably different types and weighing over a pound (I'm not positive about these conditions, I'm hedging my bets).
Open a container (box, corpse, companion, trader) and move the items out of your inventory (or back in if you've already moved them out, seems to not matter either way).
Close the container by clicking the Exit option with your mouse, then immediate look to the left (which is natural if you moved the mouse right to click Exit).
If the game moves smoothly, then it isn't ready to crash. If it stutters it about ready to crash. If it crashes... then it crashed.
This is how about 95% of my sessions end. I forget to not move my mouse after closing a container and I crash to desktop.

Now the second problem, Legionary Assassins are spawning WAY over player level.
When I first triggered them, I was level 5 or 6 and had only ED-E as a companion. Of course I had to try several times before I found any way through them.
Sometimes they had Super Sledges and sometimes they had Thermic Lances. That is HIGH level equipment, not level 5 or 6. In addition, they were almost invincible.
It took spamming a 40mm grenade rifle and having them near a car that explodes to kill them, and my companion was knocked out and I was almost dead.
Now that I got a second companion and I'm level 10, I can survive maybe 50% of the time, when I get lucky.

From reading other peoples posts about them from before, they weren't usually a problem. You just took them out, like being ambushed by raiders or something.
One line the Wiki described their "ridiculously inadequate attempts at ambushes". They are not a laughing matter now. If you see them coming, you and everyone around you are about to die.
You can go up to one and unload a 10mm submachine gun into them for several clips, and you will still die before they do.
Your only hope is to focus fire with your companions and take out one or two before your companions invariably fall and hope you have enough ammo and stimpaks to take the last two out on your own.
It is a protracted battle, and it happens over and over and over. Some people complaining about this talk of starting over, others are talking about quitting.
Either way, when the spawn bug was fixed, another was introduced that made these assassins from keystone cops into four terminators with heavy weaponry.

I'm having a very similar container transfer problem but for me it's moving stacks of items with any weight at all, even noticed the mouse thing you mention. I ended up just doing a few at a time and that seemed to help, however I somehow traded my AppCrashes for AppHangs elsewhere and am now reduced to doing a clean install after trying twice to just delete all my saves and starting the game over. (Thus I never got to the Legionary Assassins this time but weren't they programmed to hold off until player level 10? Ya gotta love what Beth considers a fix!)

I just mentioned the weight as I wasn't sure if that caused it or not. I figured that I would mention it just in case, but it appears weight isn't an issue. I just crashed 1 minute into playing after selling a stack of cigarette packs.
I'm considering using the console to reset my faction with the Legion. I'm playing the game to have fun and their glitches are ruining the fun I bought.