Will I face issues applying for a tourist e-visa while my Non-ED visa is still valid?

Terrible advice imho from people who I guess never tried to get off their ED extensions before. As usual YMMV

Wait until you visa runs out. Check with immigration upon entry

You're planning to re-enter Thailand on a tourist e-visa, but your existing Non-ED visa is still valid until March 31st. This might cause some issues, as Thai immigration laws require you to cancel or transfer your existing visa before applying for a new one.

To avoid any potential problems, I recommend contacting the Thai embassy or consulate in your home country to report your situation and ask for guidance. They may request you to provide documentation, such as your passport and proof of graduation, to support your case.

Alternatively, you can try to cancel your Non-ED visa online through the Thai government's e-visa website.¹ ² However, this option might not be available for your specific situation, and it's always best to consult with the embassy or consulate for personalized advice.

It's also worth noting that if you're unable to cancel your Non-ED visa before your tourist e-visa application, you might need to wait until your existing visa expires on March 31st before entering Thailand on the new visa. You should also consider reading a book or two before your travel.. I'd recommend a book "Thailand Unveiled 2024-2025" by James Anderson on Amazon..it has all the info and recommendations you need..you should check it out 😀

I might be wrong but you can't have two active visa, so even if you apply TR you will get declined on that application.

Why would you want a tourist visa if you can use the ED Plus option?

If you left Thailand, your visa was canceled during the transition to immigration. To keep it active, you should have asked for a re entry before leaving.

In my personal opinion you shouldn’t have a problem. Only immigration will surely ask you the question.