Whole group invisible at render

[Jkoseattle]

I have an admittedly too long project. I expect to hear something like "For projects this long there are bound to be some glitches", but here I go anyway...

At about frame 23000 I introduce two groups, each containing a vector and a text layer with some gradient on it. At design time everything looks fine, but when I render, one of these two groups does not appear at all. The two groups are basically identical, except they are in different parts of the screen. I tried fixing it by rendering just the section of the project containing the groups, but same result. Any idea why this might be happening?

[synthsin75]

Did you set the group to not render?
What about visibility and opacity?