it means that their time is confined (limited/restricted)

Btw, this is kind of related although it is not about throttling time, but instead about throttling requests. As a web developer, I often have to write code that throttles requests coming into an API from apps. This is done so the web server is not taken down by the load. So an application can hit a URL only x number of times within a specific amount of time. For instance, only 30 requests per minute. If an app attempts more than 30 requests per second, that is detected and the app's requests are dropped/ignored instead of processed for a given amount of time.

When you are looking at dictionaries, you should always make sure that you have the right part of speech. If you look at the form "throttled", it's clear that you're dealing with a verb. Had you looked for the verb, you would have found the meaning of strangle or choke - as in restricting the amount of air available to a person. This would have given you a better clue for the meaning of this expression. "Time-throttled" suggests that people weren't given adequate time to formulate an answer. That said, it's certainly not a standard combination of words. I understand what it means, but I have never once heard it before. It seems to be more of an image than an accepted term.