Cannot run arm builds (matrix build)

I am migrating from 0.8 to v1 with a matrix build for arm/amd64

Arm agent does not seem to get any builds, while amd64 tries to build both amd64 and arm one after another.

Server shows these logs about arm agent:

{“arch”:“amd64”,“kernel”:"",“kind”:“pipeline”,“level”:“debug”,“msg”:“manager: context canceled”,“os”:“linux”,“time”:“2019-07-30T21:24:34Z”,“type”:“docker”,“variant”:""}
{“arch”:“amd64”,“kernel”:"",“kind”:“pipeline”,“level”:“debug”,“msg”:“manager: request queue item”,“os”:“linux”,“time”:“2019-07-30T21:24:34Z”,“type”:“docker”,“variant”:""}

Arm agent shows nothing in the log, is there a way to debug?

I have managed to fix this by converting the config to jsonnet.