There seems to be a pervasive issue with Rotten Tomatoes links breaking. The explanation from the previous posts is:
The RT scores were improved several weeks ago, but data refreshes are required to pull in the scores. A lot of items should have naturally updated, but older or not recently refreshed items won’t have scores yet.
I think the solution would be for Trakt to set some sort of auto-refresh on their end, maybe once a week, or every couple of weeks?