I am not on a new visa now. But I have been filling out the TM30 when returning to Thailand for many years now.
I know people debate whether it has to be done or not. Some immigration offices/officers ask for the TM30 when you go there to apply for extensions and so on, others do not. I was actually asked for it when I asked for a residency statement for my driving license renewal about 3 years ago, for example.
Some say you need to fill in the TM30 when traveling in Thailand and returning to your own condo, some say you do not have to. Some say you have to fill in the TM30 always when returning from abroad, some say you only have to do it if you have a new visa. Some say you only have to do it if you change your address in Thailand. And so on and so forth.
I know all this is cause for worry and frustration for many of those who do not have an account on the Immigration website for registering TM30 info online. But I do, and it only takes me a few minutes to get it done when I enter my condo, so I do it just to be safe. And this is why I wanted to make sure I would not run into problems with the online form this time when reading that the TM6 is currently not issued.