I'm running into the same thing with a slight variation.
* My server is in GMT-6.
* My timezone GMT-6, and so reflected in my user profile.
* PiCal setting "Timezone of the server" is set to "value of XOOPS config," which is, of course, GMT-6.
* Events are entered as GMT-6.
They all display correctly to an anonymous user, but when I log in (and I assume other registered users in my timezone), they're listed 6 hours later than they should be. Of course, this also makes events listed after 5pm appear in the wee hours of the following day.
What am I doing wrong?