Bad cpu use with some process

[VitorMeirelesOliveira]

 * csd version ('dpkg --list | grep cinnamon-settings-daemon' in Mint/Ubuntu)
 * Distribution - (Mint 17.2, Arch, Fedora 25, etc...)
 * Graphics hardware *and* driver used
 * 32 or 64 bit

-> ii cinnamon-settings-daemon 4.6.4+ulyana amd64 daemon handling the Cinnamon session settings

-> Linux Mint 20 - Cinnamon 64-bit

-> GTX 1050 TI/PCEi/SSE2
Driver -> nvidia-driver-450

Issue

Some software, as Libreoffice, the escalator can not deal with it. I have 16 cores and mint uses only 1 of them when Lbreoffice starts, it makes my CPU work burning.

Steps to reproduce
Just try to use the same version and start libreoffice watching system monitor.

Ps.: If the file is new or empty the behavior is ok. So, try to reproduce using an already written file.

Expected behavior
One CPU goes to 100% of use.

Other information
LibreOffice writer version

Version: 6.4.6.2
Build ID: 1:6.4.6-0ubuntu0.20.04.1
CPU threads: 12; OS: Linux 5.4; UI render: default; VCL: gtk3;
Locale: en-US (en_US.UTF-8); UI-Language: en-US
Calc: threaded