Just a small thing, the letters upper case i and lowercase l seems exactly same with Ubuntu Desktop’s (18.04) default font which makes me confuse time to time.
They don’t look the same to me, so the issue may be specific to a language, application, setting, or situation.
Also, what you are describing seems like a bug, so I’m closing it here.
Please file a bug report with sufficient detail so somebody who has a stock install of 18.04 in a different part of the world can reproduce the issue.