Strange error "`1=1': not a valid identifier" that occurred during every job in one project

Hello, Today I started getting an error during running jobs in one of my projects:

Running with gitlab-runner 12.3.0 (a8a019e0)
  on docker-auto-scale ed2dce3a
Using Docker executor with image ruby:2.5 ...
Pulling docker image ruby:2.5 ...
Using docker image sha256:1b5e4540e7038918c20a64a76f30ccfd33bbb63de28f0c805cce286f9d49c785 for ruby:2.5 ...
Running on runner-ed2dce3a-project-14437862-concurrent-0 via runner-ed2dce3a-srm-1569949263-0c3f639e...
/bin/bash: line 80: export: `1=1': not a valid identifier
/bin/bash: line 80: export: `1=1': not a valid identifier
ERROR: Job failed: exit code 1

Configuration in .gitlab-ci.yml (I reduce it to most simple one, but issue still exists):

stages:
  - test


test job:
  stage: test
  script:
    - echo "simple job"

But error still occurred. Information that I gathered:

  • issue exists in only one of my projects,
  • Im using shared runner,
  • Issue occurred either on default docker image or custom one,
  • previous jobs, that were successful, are also failing when I rerun them,
  • issue started occurring today but last, successful build, was on 25th September.

Did anyone encounter such problem?

Update:

  • pipeline id: #85811805
  • commit hash: 598c3583c54005b991d17982ba3152cbf553930d
Edited by kk