1) If you run a project with zero resource share or project weight typically for 'backup' projects whenever your favorite project has no work, you will get only one (1) task. Other cores will go idle and when hitting update you will be told the cache is full.

2) Between 7.4.26 and 7.4.27 the reason why work was not send has descriptions that have regressed to those of 7.2. E.g. in 7.4.26 the log posts

16-Nov-2014 23:37:06 [World Community Grid] [sched_op] Starting scheduler request
16-Nov-2014 23:37:06 [World Community Grid] Sending scheduler request: Requested by user.
16-Nov-2014 23:37:06 [World Community Grid] Not requesting tasks: don't need (job cache full)
16-Nov-2014 23:37:06 [World Community Grid] [sched_op] CPU work request: 0.00 seconds; 0.00 devices

in 7.4.27 the log just print the short

16-Nov-2014 23:53:40 [World Community Grid] [sched_op] Starting scheduler request
16-Nov-2014 23:53:40 [World Community Grid] Sending scheduler request: Requested by user.
16-Nov-2014 23:53:40 [World Community Grid] Not requesting tasks: don't need ()
16-Nov-2014 23:53:40 [World Community Grid] [sched_op] CPU work request: 0.00 seconds; 0.00 devices
16-Nov-2014 23:53:44 [World Community Grid] Scheduler request completed

3) Also, you might find that you cannot re-attach to wcg. Follow either of the two workarounds posted in this thread as from here: http://www.worldcommunitygrid.org/forums/wcg/viewpostinthread?post=475210

Do not know if this is wcg specific but suspect so, because of it's https/secure operation being broken in latest 7.4. Detaching from simap and reattaching did not pose a problem with 7.4.27