Error with HighestWeightModule

[mecejide]

gap> A:=RealFormById("A",2,1);
<Lie algebra of dimension 8 over SqrtField>
gap> HighestWeightModule(A,[1,1]);
Error, DENOMINATOR_RAT: must be a rational (not a positional object)
*[1] func( C[i] )
@ /opt/gap-4.16.0/lib/coll.gi:651
[2] List( cf, DenominatorRat )
@ /opt/gap-4.16.0/lib/lierep.gi:3298
[3] NormalizedLeftReduction( novar, GB, lms, lmtab, comp )
@ /opt/gap-4.16.0/lib/lierep.gi:3639
<function "HighestWeightModule for a Lie algebra and a list of non-negative integers">( )
called from read-eval loop at stdin:3
type 'quit;' to quit to outer loop