request merge isn't be handlerded

[pinker-god]

this jenkins job log:

Building remotely on csii97 in workspace /home/jenkins/slave/workspace/dcgitlab/channel/mergecore
 > git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from 2 remote Git repositories
 > git config remote.origin.url http://****/channel/core.git # timeout=10
Fetching upstream changes from http://****/channel/core.git
 > git --version # timeout=10
using GIT_ASKPASS to set credentials 
 > git fetch --tags --progress http://****/channel/core.git +refs/heads/*:refs/remotes/origin/*
 > git config remote.origin1.url http://****/liuyongheng/core.git # timeout=10
Fetching upstream changes from http://****/liuyongheng/core.git
using GIT_ASKPASS to set credentials 
 > git fetch --tags --progress http://****/liuyongheng/core.git +refs/heads/*:refs/remotes/origin1/*
 > git rev-parse refs/remotes/origin/master^{commit} # timeout=10
 > git rev-parse refs/remotes/origin/refs/remotes/origin/master^{commit} # timeout=10
 > git rev-parse refs/remotes/origin/master^{commit} # timeout=10
 > git rev-parse refs/remotes/origin1/refs/remotes/origin/master^{commit} # timeout=10
Merging Revision 1ca7426995a8fcf3add60095f62fda61cb0937e7 (refs/remotes/origin/master) to origin/master, UserMergeOptions{mergeRemote='origin', mergeTarget='${gitlabTargetBranch}', mergeStrategy='default', fastForwardMode='--no-ff'}
 > git rev-parse origin/master^{commit} # timeout=10
 > git config core.sparsecheckout # timeout=10
 > git checkout -f origin/master
 > git merge --no-ff 1ca7426995a8fcf3add60095f62fda61cb0937e7 # timeout=10
 > git rev-parse HEAD^{commit} # timeout=10
Seen branch in repository central/master
Seen branch in repository origin/master
Seen branch in repository origin1/master
Seen branch in repository private/master
Seen 4 remote branches
 > git tag -l # timeout=10
Checking out Revision 1ca7426995a8fcf3add60095f62fda61cb0937e7 (central/master, origin/master, origin/master)
 > git config core.sparsecheckout # timeout=10
 > git checkout -f 1ca7426995a8fcf3add60095f62fda61cb0937e7
Commit message: "整理脚本"
 > git rev-list 116f9fccf954021a60ac4f267e74f8e6e158fe11 # timeout=10
 > git rev-list 116f9fccf954021a60ac4f267e74f8e6e158fe11 # timeout=10
[mergecore] $ /home/apache-maven-3.5.0/bin/mvn -f main/pom.xml clean test -U

but we found in this job's workspace of jenkins wasn't correctly merged(seems as same as the source code from origin) and i think the source and the target of pull request may be not merged( have selected merge before build), i sure i according to the doc to config.