Issue with Defined User function (in FW 7820)

[salvomic]

I had a few defined function (shift + D, and so on).
Now I find them in CK below "Variables" section, but each has "Error: Invalid Object" as value, and in the Prime doesn't work at all.

What happened?

Salvo

EDIT: I recreated one of it, then Prime reset as I refresh the calc in CK :-(
in Mem -> User Variables I find two of them with error, I delete them, but when Prime reset they are newly created...

Any help?

EDIT 2: after a restore the Prime doesn't reset, but if I cancel the last user variable ("ramp", ex definite function), and then I reset with on+Symb, the variable is recreated "magically"...