regression in lambert_w (in Maxima 5.28 for Windows)



Hello,

I get the following error in Maxima 5.28 on Windows (it works with 
Maxima 5.27, also on Windows) :

(%i15) lambert_w(1), numer;
Maxima encountered a Lisp error:
  Error in MACSYMA-TOP-LEVEL [or a callee]: No matching method for the 
generic-function #<compiled-closure BIGFLOAT-IMPL:EPSILON>,
when called with arguments (1).
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.


However, the following work (in both 5.27 and 5.28) :
lambert_w(1.0);
lambert_w(1), bfloat;