Password characters / letters auto-duplicate

[ezandro]

Using updated Firefox or built-in browser on tablet with screen touch keyboard.
PROSCAN PLT7044K-B, model MID704; A. VERSION 4.1.1, no Google Play store access.

when I enter password (e.g. for Amazon login) typed is duplicated. Final password shows at least 3 times the intended length. Example geneva11, stars are shown and for half second characters are diplayed, the last 2 if there is more than 1:

g *
e *ge
n *en
e *ne

and so in, problem is:
the displayed characters / letters are added to the already entered / typed password.
Half a solution is to type next character, then backspace the 2 shown, then enter again the wanted:
n *en
backspace 3 times (2 are not enough, the wanted must be eliminated too)
n
This time nothing new is displayed.
This reapeats for every letter typed in, after a while the count is lost, there is no way to view the already entered letters.

This seems to be locked to Amazon.com, may be other url's I have not seen. Poor amazon input fields get covered by keyboard, for extra hardship in using it.
thanks for helping to solve.
ezandro