Given

\underset {under} {over}

Expected

Actual

Uncaught ParseError: KaTeX parse error: Expected '}', got '\underset' at position 23: style{\underset̲ {under} {over

Request for help

We've got this formula:

F-1,6-BP \underset {F-1,6-BP} {\longrightarrow} F6P + P_{i}

which renders in MathJax successfully like this:

How can I modify this formula so that it renders successfully in KaTeX?