The documentation does not indicate an upper limit to the number of arguments available in an alias.

Expected:
Tag
@test{arg1=1,arg2=2,arg3=3,arg4=4,arg5=5,arg6=6,arg7=7,arg8=8,arg9=9,arg10=10}

AlIASES entry:
test{1}=@details\n(\@test=\1)\n \
test{2}=@details\n(\@test=\1,\2)\n \
test{3}=@details\n(\@test=\1,\2,\3)\n \
test{4}=@details\n(\@test=\1,\2,\3,\4)\n \
test{5}=@details\n(\@test=\1,\2,\3,\4,\5)\n \
test{6}=@details\n(\@test=\1,\2,\3,\4,\5,\6)\n \
test{7}=@details\n(\@test=\1,\2,\3,\4,\5,\6,\7)\n \
test{8}=@details\n(\@test=\1,\2,\3,\4,\5,\6,\7,\8)\n \
test{9}=@details\n(\@test=\1,\2,\3,\4,\5,\6,\7,\8,\9)\n \
test{9}=@details\n(\@test=\1,\2,\3,\4,\5,\6,\7,\8,\9,\10)\n \

When ten arguments are used it is expected that they all function.

Found:
When 10-19 arguments are used, they are replaced by the first argument. When 20-29 are used they are replaced by the second argument, etc..

The alias argument parsing, in the method 'replaceAliasArgument' on LN 6549 in util.cpp, should be iterated in reverse to capture alias arguments larger than a single digit.