coefficients doesn't work over FreeAlgebraQuotient with arbitrary basis

[mahrud]

Perhaps this is not the intended usage of coefficients, but I was always glad that it worked:

i1 : R = ZZ/11[x,y];

i2 : coefficients(x-y, Monomials => {x-y})

o2 = (| x-y |, {1} | 1 |)

However, it doesn't seem to work using AssociativeAlgebras:

i3 : needsPackage "AssociativeAlgebras"

o3 = AssociativeAlgebras

o3 : Package

i4 : A = ZZ/11<|x,y|>/(x*y-y*x);

i5 : coefficients(x-y, Monomials => {x-y})
stdio:5:12:(3): error: wrong number of rows or columns

cc: @mikestillman @moorewf

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Tangentially, I'm surprised this happens:

i19 : R = ZZ/11[x,y];

i20 : times coefficients(x-y, Monomials => {x,y})

o20 = | x-y |

              1      1
o20 : Matrix R  <-- R

i21 : times coefficients(x-y, Monomials => {x,-y})

o21 = | x+y |

              1      1
o21 : Matrix R  <-- R