4.0pre1 fails with indent

I opened a file which started like this:

:mode=text:

TODO

11/9/01

When I opened this file, the buffer said

:mode=text: [11 lines]

and then, when I tried to expand it, displayed nothing
at all. I think it's getting confused on the trailing
colon.

I'm running 4.0pre1 on W2K using 1.3.1_01