Installing a new 4-way switch troubleshooting

I’m installing a new 4-way switch.

When I flip any of the switches, it’s not toggling the on/off state of the final hot wire. The final hot wire (which will supply the light) is always hot. All the travelers are always hot.

Something is supplying continuous power. I’m not sure what I did wrong. I checked these things:

• I tested each switch, they’re not faulty and are all showing correct continuity.
• I checked the neutrals and the grounds, they’re not hot.
• I turned off all other circuits in the house, it’s not accidentally connected to another circuit.

Any ideas?

I wired it like this:

Here are some photos of the actual wiring:

Switch 1 — the three-way switch is on the left, the other is a single-pole switch supplying another light. They’re both connected to the supply power.

Switch 2 — 4-way switch

Switch 3 — last 3-way switch (connected to light)