Arda

Just saw your input, sorry I was at work. Today, I've tried both 1.9.2 and the 1.9.3 which are very recent versions released in this last 2 days, and I can confirm 1.9.3 fixed the issue on ARMBian Debian.
 
The changelog has a line like this:
 
 
I don't know if this was the reason, however one of the fixes pushed to release from 1.9.2 to 1.9.3 fixed it on ARMBian Debian (I wiped the SD card 2 times to double check).
 
This thread can be marked as solved :-)
 
Thanks for your time!

I checked datasheet and board schematic and only setting possible is to select polarity. For any permanent disabling, HW solution must be used.

So if you did try setting another upstream servers in dnsmasq config and it worked for you, then it's definitely related to dnscrypt.
Let's forget for a moment about systemd sockets. dnscrypt-proxy bind address should be controlled by "-a" parameter, try using it to bind to 127.0.0.3 for example, and using strace if it fails.
And let's wait for more reports here.