Description:
Hi! I am having font rendering issues in Writer for some time now. When I scroll-down/up, it breaks the rendering of some lines of text at random.

This happens in all Writer documents, but at random. When a line is ill rendered, if I scroll-up until the line is outside my view and then return, then it renders correctly. But later some other line will get the same issue.

I also noticed that when I click on a line, the height of text sometimes changes.

I attached an ODG file with some screenshots I took demonstrating the issue.

Steps to Reproduce:
1.Create a text file with many pages of text
2.Edit the file for a while
3.At random the rendering issues will appear
4.To make the rendering problem disappear from a certain line, just scroll-up until the line is out of view, and then return

Actual Results:
Text is ill-rendered, as shown in the attached file

Expected Results:
Correct rendering of the text


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 7.0.4.2
Build ID: 00(Build:2)
CPU threads: 16; OS: Linux 5.8; UI render: default; VCL: kf5
Locale: pt-BR (pt_BR.UTF-8); UI: en-US
Ubuntu package version: 1:7.0.4~rc2-0ubuntu0.20.10.1~lo1
Calc: threaded