Sorry for the very delayed reply, I forgot I had made this plugin! I’ll try to keep an eye on here and keep it updated where possible but I have little use for this plugin now. It was originally meant to just allow links to be placed in the title but it should have worked with any HTML. WordPress is a massively complicated beast when it comes to stuff like this.
As @abumalick said this plugin is ridiculously simple – the readme file has more lines! This is both advantageous, and disadvantageous. The plugin does nothing else so shouldn’t really have bugs. However the other way of looking at it, is it doesn’t do anything fancy, so it could have unexpected results with different themes/plugins.
What version of WordPress are you running?
What other plugins are you using?
What theme are you using?
Does it still happen with the 2015 or 2016 theme?
Does it still happen when you disable every other plugin?
I’ve found that it occurs with any “space” or whitespace character inserted in there. It’s interesting that if you use ” ” it doesn’t mind it but of course you can’t use that to separate two classes.