Arm64 failing without message

We are currently seeing pretty persistent failures of our Arm64 job. This has happened in the past and usually, a re-run fixed the situation. However, currently for some pull requests, the job fails persistently even after multiple tries.

Typical behavior: The job runs much slower than usual and fails after ~1h 15min without a failure message.

Examples:
https://travis-ci.org/github/bitcoin/bitcoin/jobs/722800235
https://travis-ci.org/github/bitcoin/bitcoin/jobs/721669035
https://travis-ci.org/github/bitcoin/bitcoin/jobs/721637126