motion - ip camera gets password encrypted?

[pw44]

Hia,
today i rebooted my core and discovered that 2 of my cameras did not showed images.
Digging, i discovered that the field password has the string: 6pl%2srvf8ssju_7u instead of: viewer
Changing from 6pl%2srvf8ssju_7u to viewer solved the problem, but then, on a new reboot, another string was there, preventing the view of the images.
Is there a way to avoid this password change?
TIA,
Paulo