Linux Hard drive encryption password invalid after memory size change

I have an almost **fresh Kali linux installation** in an Hyper-V virtual machine. It is **configured with hard disk encryption** during installation. After some working days, I **reduced the amount of RAM** memory reserved for the VM, but when I boot up the reconfigured machine, the **password** used to decrypt the hard drive is **reported as invalid**. The reported error is:

: ERROR: sdaX_crypt: cryptsetup failed, bad password or options?

If I undo the configuration change the password is valid again... Does exist a relation between the LUKS decryption algorithm and the machine memory size? It doesn't have sense, in my opinion. Which can be the reason? Thanks in advance.