echo "The Quick Brown Fox asdf\nasdf TQBF asdf\nasdf TWBF" | ug -i 'the.quick.brown|TWBF|TQBF'
1: The Quick Brown Fox asdf
Seems it happens when the first character is the same and -i is used
echo "The Quick Brown Fox asdf\nasdf TQBF asdf\nasdf TWBF" | ug -i 'the.quick.brown|WBF|QBF'
1: The Quick Brown Fox asdf
2: asdf TQBF asdf
3: asdf TWBF