[eclipse-clp-users] Possible bug in nth1/3?

Hello,

Is there any explanation for the following behaviour?
Thanks in advance.

Regards,
Panagiotis

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$ eclipse
ECLiPSe Constraint Logic Programming System [kernel threads]
Kernel and basic libraries copyright Cisco Systems, Inc.
and subject to the Cisco-style Mozilla Public Licence 1.1
(see legal/cmpl.txt or http://eclipseclp.org/licence)
Source available at www.sourceforge.org/projects/eclipse-clp
GMP library copyright Free Software Foundation, see legal/lgpl.txt
For other libraries see their individual copyright notices
Version 7.0 #45 (x86_64_linux), Mon Feb 25 22:43 2019
[eclipse 1]: lib(listut).
source_processor.eco loaded in 0.00 seconds
hash.eco   loaded in 0.00 seconds
compiler_common.eco loaded in 0.01 seconds
compiler_normalise.eco loaded in 0.00 seconds
compiler_map.eco loaded in 0.00 seconds
compiler_analysis.eco loaded in 0.00 seconds
compiler_peephole.eco loaded in 0.00 seconds
compiler_codegen.eco loaded in 0.01 seconds
compiler_varclass.eco loaded in 0.00 seconds
compiler_indexing.eco loaded in 0.00 seconds
compiler_regassign.eco loaded in 0.00 seconds
asm.eco    loaded in 0.01 seconds
module_options.eco loaded in 0.00 seconds
ecl_compiler.eco loaded in 0.05 seconds
File listut.pl, line 199: Singleton variable X
File listut.pl, line 201: Singleton variable El
/usr/local/eclipse/lib/listut.pl compiled 19824 bytes in 0.02 seconds

Yes (0.06s cpu)
[eclipse 2]: nth1(8,[a,b,c,d,e,f,g,h,i,j,k],V).

V = h
Yes (0.00s cpu)
[eclipse 3]: nth1(9,[a,b,c,d,e,f,g,h,i,j,k],V).

V = V
Yes (0.00s cpu)
[eclipse 4]: nth1(10,[a,b,c,d,e,f,g,h,i,j,k],V).

V = V
Yes (0.00s cpu)