EU Toyota Yaris - PCS error when crossing line without blinker

Cross-reference: https://github.com/sunnypilot/opendbc/issues/364

After discovering the issue in Sunnypilot fork, I tested with nightly-dev of stock OP: same issue persists.

In essence:
PCS error is triggered when I cross the line without active blinker. It stays on my dash until car is rebooted.
This happens regardless of whether ACC is on or off. Just having enabled openpilot and driving triggers it.

Setup:
- EU Toyota Yaris 2020
- OP nightly-dev, commit `051d25ca`
- radar ACC + SecOC car
- chill mode, no long control, I am using stock radar and OP for lateral

Normally, this wouldn't be a problem, but stock camera detects a lot of stuff and this error is triggered during normal rides, even when OP is in control.

# Logs

| Drive ID | PCS error timestamp | Notes |
|--------|--------|--------|
| ee526f711ff50e03/00000003--ec2971f987 | 1:05 (65s) | ACC not enabled |
| ee526f711ff50e03/00000002--a8e07eac78 | 0:42 (42s) | ACC not enabled |
| ee526f711ff50e03/00000001--2e0459bbe5 | 0:50 (50s) | ACC not enabled |
| ee526f711ff50e03/00000004--5b1e214211 | 1:43 (103s) | ACC enabled |

# Analysis

What can I see on CAN?
- LKAS camera sees the lines & detect lane departure (seen on bus 2)
- LKAS sets STEER_REQUEST and STEER_REQUEST_2 (STEERING_LTA_2), but those requests are blocked by OP, so nothing changing on bus 130
- PCS error is triggered, shown by PCS_INDICATOR in PCS_HUD frame on bus 0
- LDA_UNAVAILABLE appears from LKAS on bus 2, but this is blocked

Observations:
- it looks like I need two line crossings to trigger error - on first one, TORQUE_WIND_DOWN is set, on second one error is triggered
- looking at bus 128 there is no decoded frame which indicates "something happening", then how come the car know to trigger PCS error? detection of line crossing can be done only by front camera AFAIK
- I see something in 'untitled' frames (0x367, 0x36D, 0x6EF) - they need a bit more investigation.
- UNKNOWN in LTA_RELATED seems also somehow connected, but I am not sure how.
- SETME_X3 in STEERING_LTA is set to "TSS 2.0" (val 3) by OP, but is set to "TSS 2.5 or 2022 RAV4" (val 1) by stock camera.

Any input/hints/help appreciated :)
Other note: Not seen on JP Yaris.