Have you checked your hardware with a simple multimeter? Most runout sensors are just a switch to ground. There is either a pull up resistor on the board or a built in pull up resistor is used in the microcontroller. This is what creates the logic high condition. The trigger is then a switch that is wired to be normally open. When the switch is triggered it pulls the pin low because the pull up resistor is a very small value. This creates the logic element required. Even if the pull up resistor is done in software, you can measure the logic high voltage with a meter. All current microcontrollers are CMOS logic levels. Look up CMOS logic on Wikipedia if you need a refresher on what this means and the respective levels and uncertainty thresholds for logic high and logic low; they are not rail to rail 0v-5v0 (or 3v3).
If you are having issues after triggering, I would look at whether the pull up resistor is in hardware or if you are using the software pull up. You may find that there are multiple pull up resistors in hardware, the module, and software all combining to create an issue (unlikely edge case). It sounds more like an issue where the only pull up resistor is in software and it is likely getting turned off after the sensor is read, or there is no pull up resistor at all and the trace and wiring are left floating. When a wire is left floating like this without a pull up or a pull down resistor, it always becomes a radio antenna that picks up all kinds of noise. This radio noise on a floating line/trace/wire/pin will create most typical sporadic behaviors like you have described. It could also be a poor connection.
If you are not familiar with digital logic and multimeters, meters are slow and cannot generally measure signals like serial communication. That is not what is happening with these kinds of sensors in most cases. I'm not at all familiar with the hardware in question, but the last time I messed with Marlin most sensors are just simple pin interrupts with pull ups. Those can be checked with a meter. I apologize if my laziness in not looking up your specific hardware has missed some advanced sensor that is using I2C or SPI. I'm just a user like you here and trying to help. That mod tag means nothing. This is just general electronics and microcontrollers advice.