A new bug with assume and reset() in Maxima 5.18.1?

With Maxima 5.18.1 there is a problem if an assumption over the same
symbol is made after a reset().


(%i2) assume(a>0);
(%o2) [a > 0]
(%i3) facts();
(%o3) [a > 0]
(%i4) reset();
(%o1) [algdelta, nobjects, +labs, current, context, lispdisp, display2d,
                                            tr-unique, linenum, %, mopl, __, _]
(%i2) assume(a>0);
Maxima encountered a Lisp error:

CAR: $ZERO is not a list

Automatically continuing.
To reenable the Lisp debugger set *debugger-hook* to nil.


In Maxima 5.17.1 there was not this problem.
After a reset(), it is impossible to make an assumption over symbols
used in the previous session.


Stefano