Fooling around with a ask.sagemath
question, and perusing the known symbolics problems (most notably
Trac#21789), I was led to reported solve problems. It seems that some tickets such as
Trac#24102 and
Trac#24477 may have a common root problem, which seems to be the mishandling of symbolic constants confused with variables in the Maxima interface.
I am out of my depth here, but put this note to the attentin of people knowing the implementation of this interface.
HTH,