No they were not at least I do not remember setting it.
Today I came to conclusion that that one device that was introduced (I use customm disco server btw) was keeping my android device (a device that was introduced and was not shared folders with) very very very busy at least that is what it was in the log, I saw that there was constantly some kind of connection, some handshaking or messaging between these devices. So I went ahead and made all the introducer=true to introducer=false then I was able to manually delete that device from the config. Since then my Android devices cpu usage went down almost %30, and syncthing is not using %15-20 constant cpu anymore.
So somehow overly chatty clients activity was causing alot of cpu usage on Android. Now you ask what is yourt proof, where are the logs? My proof is my experience, and I did not have time to get the logs. Just sharing my experience.
I will see if I can get some logs from other devices that are in the same situation, I have not fixed on some. Do you want any special log?