I have been trying to use this feature with using my unused switch from my Z sensor when I added a BL Touch. I have built firmware with using the “low” option and “high” option and both wont print as it says i need to change filament despite being new roles.
I got the same issue, and I tried with 2 sensors (thought 1st one was broken). After some time from starting print, it replaces PLA. I have also tried with PLA in sensor and without while PLA is being feed separately and same result. Have you solved it?