I found out that only in the two submenus Setup/Recording, Playback & Timeshift, in the two submenus for Rec&Play and the other one for TS is not possible to go down.
It happens only in these two submenus, as far as I know and, obviously, it does not depend on the RCU because
1) it does it with every RCU units I've got;
2) It does it also by OWIF.
3) It does the same also in OBH 4.4.008.
EDIT after replacing Recordings.pyo and Timeshift.pyo from older images
Replacing the two file above mentioned in /usr/lib/enigma2/python/Screens Timeshift submenu works, whilst Rec&Play crashes.
But the issue it's almost surely due to some change in these two files or also some other ones.
Regards.ViX-Rec-menu.jpg