Windows shell executor (bash) fails with 1.4.0: "GIT_SSL_CAINFO: No such file or directory"

I updated from gitlab-runner 1.3.0 to 1.4.0 and now my builds fail with the following message

Running with gitlab-ci-multi-runner 1.4.0 (5dd9b2f)
Using Shell executor...
Running on BUILD1...
bash: line 51: /e/Multi-Runner/E:/Multi-Runner/builds/483a0fb2/0/my-namespace/my-project.tmp/GIT_SSL_CAINFO: No such file or directory
ERROR: Build failed: exit status 1

The file E:/Multi-Runner/builds/483a0fb2/0/my-namespace/my-project.tmp/GIT_SSL_CAINFO exists. Since I am using shell executor with bash on windows. The path to the file should be:

• /e/Multi-Runner/builds/483a0fb2/0/my-namespace/my-project.tmp/GIT_SSL_CAINFO and not
• /e/Multi-Runner/E:/Multi-Runner/builds/483a0fb2/0/my-namespace/my-project.tmp/GIT_SSL_CAINFO

This is my config.toml

concurrent = 3

[[runners]]
  name = "BUILD1"
  url = "https://git.domain.tld/ci"
  token = "..."
  tls-ca-file = ""
  executor = "shell"
  shell = "bash"
  [runners.ssh]
  [runners.docker]
    image = ""
    privileged = false
  [runners.parallels]
    base_name = ""
  [runners.virtualbox]
    base_name = ""

After downgrade to gitlab-runner 1.3.0 the builds succed again.