When pressing enter, it adds an additional space character into the new line.
An extra space character
I updated the installer version by downloading the new AppImage and the bug is still there
I can’t reproduce this (same OS, Obsidian 0.9.4, Installer 0.9.2) and never had this problem so far.
Could it rather be related to any of your settings?
UPDATE:
It was caused by wrongly typed html snipped. In <mark>text </mark> it had backslash instead of normal slash. Editor did not consider the snippet closed (despite working fine) and kept adding extra spaces
<mark>text </mark>