Hi Aadi, speed doesn't go super fast when sims are sleeping in the tents, just the way the game works.
Also the read the wilderness digest interaction just about always gets queued up... no idea why but it's probably easier to ignore it until its almost time for the sim to wake up. Least that way you don't need to be continuously canceling it all night long. It does give the sims a fun boost so although annoying at least it is somewhat useful.
It is probably a bug and if it is, it's my guess that EA won't spend time fixing that just yet when there are other bugs that are higher priority.