My questions a
1. Is the spackle bulging now only because I did a ****-poor job, or
maybe because the sheets are actually moving together now? (Perhaps because
of hot summer temperatures?)

Probably a combination of both.


2. Was my fix adequate? Should I have put joint tape on, or something
more drastic?

You need joint tape on joints. That's why they do it in the first
place on proper butt joints. Yours is 1/4 inch, where it's even more
important.

3. What would you do now? (Short of unloading the house-- the wife is
attached now.)

If it's bad enough that you want to fix it, then clean all the loose
material out. Fill the gap with joint compound. Then put down the
mesh type of tape over it, followed by more joint compound. It will
take 3 applications, each feathered out wider to do it right.

But, there are some joints and situations where it may very well crack
again due to settling, contraction expansion, etc. More so in homes
where the temp/humidity is allowed to range a lot.




Any thoughts or comments would be most welcome.

-Travis