Running " tr [A-Z] [a-z]" in a particular directory gives unexpected output

Issue

• tr command working unexpectedly
• Running tr command gives wrong output in dir1 directory. Expected output is anil.

 [root@server dir1]# echo ANIL | tr [A-Z] [a-z]
  aaaa

• Running same command in another directory dir2 gives correct output.

 [root@server dir2]# echo ANIL | tr [A-Z] [a-z]
  anil