If you click on the Description column, the list changes to be sorted on Description and an upward arrow appears next to the word "Description" (as you would expect).
If you then click the Go Up arrow, to go up a level, and then double click the folder to go back into it, the list appears sorted in Name order (not in Description order). However the upward arrow still appears next to the word Description.
I can't reproduce that, except for the expected behaviour that the list is sorted by Name initially, and the arrow next to the Description column is red, until all the descriptions have been loaded. Once the descriptions are loaded, the arrow turns black and the list is re-sorted by Description.
It may be worth grabbing the latest beta version (link in my signature) if you're not already using it, in case that helps. (It's the version I'm testing with, and there was an issue fixed recently with sorting by folder size when the sizes were calculated really quickly, so that may be relevant. The current beta has proven to be stable so you can install it without worrying.)
Thanks. I've installed the beta and that seems to have solved the problem.