Strange issue with pushing large files to Bitbucket server

[GSHerber]

We are experiencing a strange issue with pushing large files to Bitbucket server. If we push 3gb files they are committed intact, 4gb files are truncated to 0 bytes and 5gb files are truncated to 1gb. This result is consistent across all our environments prod\dev\test Windows and Linux and testing with files of 3gb, 4gb and 5gb. This is Bitbucket server v7.17.4, Git v2.33.0. We have checked proxy configurations and there is no limit set for file transfers, i.e. the file size limit check is disabled. No network restrictions such as IPS, DLP etc. No Antivirus intervention. Anyone seen this before?