I have the same problem with a Dell Desktop XPS 8700 running Windows 8.1 Pro.
You have joined an ever increasing in length thread on this problem, no-one seems to have found the answer yet (months) although there are some earlier suggestions worth trying.
I have wrestled with the problem for 18 months, the most times I have had to input my password before success was 6, the average is probably 2. It happens about 70% of the time.
Updating the BIOS seems to have made a marginal improvement.
The good news is that I have never been completely locked out.....yet !
The variation on devices/brands suggests to me that this is a Microsoft issue.
I am sticking with it until Windows 10 appears later in the year and hopefully that will be the end of it, otherwise it is off to TruCrypt successor VeraCrypt.