Test case: Not all svgs display this behaviour; an example "problem" svg is https://upload.wikimedia.org/wikipedia/commons/c/cc/Noto_Emoji_Oreo_1f914.svg
Add this svg to a LibreOffice document (bug seen in both Writer and Impress) via Insert->Image. Extraneous blue lines appear in the top left corner of the image; no such lines are visible when viewing the SVG outside of LO; it should be transparent in that area. The lines are visible both in the editor and in an exported PDF. Example: https://people.collabora.com/~alyssa/Bluelines.odp (export https://people.collabora.com/~alyssa/Bluelines.pdf)
Tested on aarch64 machine (armv8); build from Debian buster.
Steps to Reproduce:
Open the linked odp.
Incorrect SVG rendering
Correct SVG rendering
User Profile Reset: Yes
Build ID: 1:6.1.5-3
CPU threads: 6; OS: Linux 5.1; UI render: default; VCL: gtk3;
Locale: es-MX (es_MX.UTF-8); Calc: group threaded
Created attachment 152710 [details]
odp displaying issue
Confirmed using LO 220.127.116.11.alpha0+ (9b7729c6e224dfbe89e309aab8e8fd392fc234ad), 18.104.22.168 / Ubuntu 18.04.
The imported SVG looks even worse before that.
Also present Windows builds.