New topic same old problem!

This is probably a question for Brian again, but help from any quarter would be greatly appreciated.
Problem is:- I use one of WD standard files ( have done so for many years) this file is “Month.html” where Month is the name of the current month. for six months now the file has been truncated by the last day of the month. Can anyone verify that this is a problem with WD or is it some setting I have miss set and in either case offer some constructive advise how to fix it, this is truly a problem as I use this file for historical data and on my web site.

no missing last day here

is WD running all the time?
also which version and build of WD?

WD Running 24/7
Ver 10.37Q B 34