1. Visit empty buffer test in fundamental mode (C-x b test RET)
2. Insert

tee << EOF
text1 $var
text2 $(echo cmd)
text3
$var2
EOF

3. Put point before "text2"
4. M-x load-library RET treesit RET
5. M-: (treesit-node-children (treesit-node-at (point) 'bash))

    => (#<treesit-node (simple_expansion) in 18-22>
        #<treesit-node (command_substitution) in 29-40>)

   Note that this list is incorrect, "$var2" at the end of heredoc is
   missing.

6. M-: (treesit-node-first-child-for-pos (treesit-node-at (point) 'bash) (point))

   => nil

   Expected return value here is #<treesit-node (command_substitution) in 29-40>

I'm not sure if this bug is on Emacs, tree-sitter-bash or even
tree-sitter itself and I don't know how to check.

tree-sitter-bash version: 0.19.0.r19.g77cf8a7-1
tree-sitter version: 0.20.7-1

Thanks and best regards.