Based on your offset, it looks like you're trying to push some really big object (offset 3453162391 =~ >= 3GB), so zlib failed on inflating/compressing the object since there was not enough room in the output buffer (error: Z_BUF_ERROR).
This could be related to temporary lack of memory, or some buffer limits. Basically it's trying to process as much input as possible using the available output, otherwise it returns Z_BUF_ERROR. See: zlib inflate returning a buffer error.
You should re-try to see if the problem can be reproduced.
If the issue is repeatable, then try to:
- avoid pushing large files into git repository, Git was designed to track the source code files, not very large files (like 6GB), 
- increase git message size on your client - http.postBuffer, e.g.
 - git config http.postBuffer 134217728 # =~ 128MB
 
- use some alternative client which can ignore larger blobs, such as - bfg, e.g.
 - java -jar bfg.jar --strip-blobs-bigger-than 100M some-big-repo.git
 
- remove the object which is causing the issue (- git gc?).
 
Other potential issues could include:
For further readings, check this post: “pack has bad object” when pushing to remote.
If you'd like to work with large files with Git, check the followings: