It looks like we are a bit short in term of memory with the current codebase and tooling. The pipelines shows weird behaviors that looks like OOM kills.
Reducing the number of stages of stages executed in parallel in the pipelines is a quick & easy solution that should be good enough for now. It should not impact the pipelines execution times too much (or at all): some stages are quite long so they run during the whole time and I'm guessing we are currently wasting a lot of time on the context switches.