Firstly I have stock v.150, no mods, etc.
Repeatable, yes.
Stall/Lag/Hang - Wares Transfer. Latest occurrence is selecting the transfer of Deployables (Missiles, sats, etc.)
Not sure exactly what causes the issue, however it seems to be attached to the simple act of telling a ship to exchange these wares.
They head to an area for the exchange, then just sit there waiting.
If you look at the queue for Orders, it's marked *Critical* and {insert timeframe} they state that they cannot fulfil the Order. Since I queued up 4 transfers, this is taking ages. It also has caused a lot of lag, CPU usage goes from 4-6% to anything from 8% to around 20%. The memory size of the game usually sits around (I'll edit with more accurate estimates when I get home) 3-4 GB, yet while these queues occur while attempting, the memory keeps increasing. The highest I've seen is approx. 8.3GB.
I have fixed this in the past with a save, quit game and restart. Then things sort themselves out.
You cannot interact with either ship, cancel the order, while this queue is trying to complete.
After going back to a previous save and trying it a different way, I changed from two medium ships to a Capital and a Medium. The medium ship then just docked and is just sitting there doing nothing. Lost access to control either ship as well. (and my current save is at this step)
Would be handy to know the time lime between an Order be issued and when it "times out". From the above two examples, the wait seems to be around 5 minutes between each Order to cancel out.
Earlier today, I did manage to get around one ships transfer but cancelling the Order. So it seems at given times, the Orders to timeout and reset. I got into the ship and proceeded to try the Capital and Medium ship, which has created the same stalemate and stuck Order queue

After the second try but a different approach, I did noticed significant lag spike occurring, combat, interaction with the UI. The newest issue to raise it's head, while trying to get around the issue, I noticed I could not select a ship from the Map screen, the Player Owned List with not show all my ships, only now and then if I have a ship in the open on a sector, I could select and then it would drop the selection while trying to issue an Order

As this is explored further, I'll add more details to how this occurs and update with more information on what seems to be a bottleneck for the Order Queue for further investigation and a possible fix.