xSemaphoreTake

I try to create a critical section using a semaphore, having two tasks trying to access the same data. My problem is that xSemaphoreTake sometimes returns before the actual timeout(blocking time)(which is around 500 mS), with pdFALSE. Anyone else seen this problem? // Fred J

xSemaphoreTake

Never come across this.  When this happens does the task block at all, or just return immediately with false?  I would be grateful for any further information. Regards.