I am developer, I saw this review right away and have been thinking about it since then.
First of all, thank you for the finding and reporting minor bug in our software.
It is indeed minor since the software have been working on 10K+ websites daily. Also it passed our tests before deployment. In fact I am using the plugin constantly on 3 different websites and still this bug didn’t reveal itself up to the moment. PHP also doesn’t report this as an error (unless you set it to treat warnings as errors).
In any case, this bug has been fixed few minutes ago – it took just few minutes.
One important note. QuickLaTeX is part of open source universe, which gives you the opportunity to be member of community and participate in development. You can send bug reports to developers using support forum, create the fixes yourself (especially for trivial bugs like this) and/or provide patches for the bugs.
This is how open source works. But, instead, you did something absolutely unethical and in-respectful – you just downgraded the overall rating of the whole project because of one bug you found.
FYI, in total 49 bugs were fixed in latest WordPress release 4.9.8. I guess you did everything to downgrade the WordPress in all accessible ways for you. And surely you abandoned such buggy framework because of so many bugs in it.
@”Also, this plugin was last updated 2 years ago.”
Even more, first version of QuickLaTeX was released 9 years ago. And some code is still in use. Many thousands on people have been using it over the years. We provide upgrades, Support our server-side to make sure everything works smoothly, etc.