factor bug with FractionField

[pzinn]

minimal example:

i1 : F=frac(QQ[x])

o1 = F

o1 : FractionField

i2 : R=F[y]/(y^6)

o2 = R

o2 : QuotientRing

i3 : factor(x^2-y^2)
stdio:3:6:(3):[1]: error: key not found in hash table:
        monoid (of class Symbol)

[pzinn]

i11 : errorDepth=0

o11 = 0

i12 : factor(x^3-y^3)
../../Macaulay2/m2/factor.m2:145:30:(1):[15]: error: key not found in hash table:
        monoid (of class Symbol)
../../Macaulay2/m2/factor.m2:145:30:(1): entering debugger (enter 'help' to see commands)
../../Macaulay2/m2/factor.m2:145:28-145:37: --source code:
        RM' := (baseRing R) RM.monoid;