Why does my option show no P&L?

Its contract multiplier is unknown. Set it on the instrument in Settings → Asset registry and the P&L computes.

When the multiplier is missing the entry form shows multiplier not set in amber and the position computes no P&L at all. That is deliberate. The alternative — falling back to price difference × quantity — books a $1.20 premium as $1.20 instead of $120, off by the contract size, and it does it silently.

An amber "unknown" you can fix in ten seconds is a much better outcome than a number that is wrong by a factor of a hundred and looks fine.