Exception thrown when attempting to read the jcheck configuration file from a Git repository

When users issue the /tag command, the Skara bot frequently throws an exception while attempting to read the jcheck file from the repository. The occurrence is quite common, and after few retries, the command will eventually be processed successfully.
However, sometimes, it can take up to 20 minutes. I don't know whether we are able to do something.

(CommitCommandWorkItem@openjdk/jfx:f7b21e54): java.io.IOException: Unexpected exit code
'git -c core.quotePath=false ls-tree -r f7b21e5468f1aad18df17443590c0887b2cf0239 .jcheck/conf' exited with status: 128
[stdout]
[stderr]
fatal: not a tree object