thrunite xp-g missing modes troubleshooting

In an attempt to upgrade an old surefire 6p, I bought a "thrunite p60-style cree XP-G R5 LED drop-in flashlight upgrade engine - 300 lumens - 3 mode (4-9V input)", but I'm not seeing the three modes. I'd expected that I would see low-medium-high when I release the switch for a short moment and then press it again, but it seems like I'm just seeing high-high-high (etc.)

Is it possible the flashlight is somehow now able to take advantage of the three modes? I'm using 2 duracell 123 primary (CR17345) cells. The drop-in just says "ThruNite" without a model number so it's hard to verify that I have exactly the product I ordered...

Could it be more complicated somehow?

Thanks!

The seller could have sent you the single mode version of the drop-in.

Contact the seller for an exchange.