What version of Thunderbird, LO, and Windows[ if that is your OS] do you have installed? That might help.
On
Thunderbird 24.3.0
LO 4.1.5.3
OS is
Linux Mint 16 with MATE
Works fine with "paste".
The formatted text was kept.
One post states that this has been "reported a zillion times". So it seems to me that it might be "system specific", if one system works while others do not.
I deal with that myself. My laptops upgraded to Ubuntu 13.10 just fine, but the desktop kept giving me too many errors. Did that the last time I upgraded the Os on the desktop. It should have worked like the laptops but it did not. That is another case of "system specific" of a issue with one system while 2 others running the same OS and having the same packages installed would not work.
So, to be honest, "system specific" issues and "bugs" are hard to find the cause and correct the issue. It could be something with the install of Thunderbird and/or LO. I know the last version of TB I had issues that the save version on a different OS does not have. I know that some packages run well with Win7 Pro while I have issues with Win7 Home [both laptops].
I hope it gets fixed for your system.