After installing Email-ext plugin git can not use global .gitconfig.

In my case in global .gitconfig required parameters are i18n.commitEncoding and i18n.logOutputEncoding. There is JENKINS-23091 (Git. Problem with encoding in the list changes) and workaround for JENKINS-23091 is set this parameters in global .gitconfig.

Steps to reproduce:
1) Jenkins without Email-ext plugin
2) Set some global parameters for git
3) Create job
4) Start build, pull from git repo in this job
5) all right in above steps (git logs are correct)
6) now install Email-ext
7) just in case restart jenkins
8) update git repo
9) start build, pull from git repo in job
10) our global parameters has not been used by git, git logs are broken

Some investigations: lists of environment variables are different before installation and after installation of Email-ext plugin. These envs are lost after Email-ext installation - HOMEDRIVE, HOMEPATH, LOGONSERVER, USERDOMAIN_ROAMINGPROFILE.