M4300 CLI issue

Hallo I have a stack of 2 x M4300 switches

(SW-STACK) #show switch

Management Standby Preconfig Plugged-in Switch Code MAC
SW Switch Status Model ID Model ID Status Version Address
--- ----------- --------- ---------------- ---------------- ------------- ----------- -------------------
1 Mgmt Sw M4300-52G-PoE+ M4300-52G-PoE+ OK 12.0.17.13 78:D2:94:B9:76:4D
2 Stack Mbr Oper Stby M4300-28G-PoE+ M4300-28G-PoE+ OK 12.0.17.13 B0:B9:8A:4F:78:30

(SW-STACK) #

I often use the CLI to configure and manage the switches.

Random, but frequently, when I access the CLI via SSH or via the CONSOLE the command line after requesting the enable password and showing the ***** , doesn't accept the password and everything follows are just ****.

I have to close the session and restart another session.

This often happen when the enable password is wrong, but sometimes when the password is ok too.

I have the same problem with firmware 12.0.17.12.

The same problem with Xterm or VT100 emulation, using SecureCRT or DOS connection.

Sometimes the problem happens when configuring users password.

After the password insertion, the CLI does not accept other commands, but always show **************.

Anyone has the same problem  ?