okay... i see that emily posted this in another thread:

emily (Remember The Milk) says:

"it only updates every few hours (so you might not see the latest tasks that you've added in RTM until it updates)."

so is it not possible to force a refresh somehow? even checking/unchecking the box or removing and adding the calendar again doesn't seem to force a refresh.

This is handled on the Google Calendar side, so unfortunately it's necessary to wait until they fetch the iCalendar URL again.