builders failing to git fetch from Googlesource

I am working on an Android Platform Tools Snap and hooking builders up to build them for the supported architectures results in these types of errors during git-fetching:

[27/May/2024:17:33:20 +0000] "CONNECT HTTP/1.1" 200 285920 "-" "git/2.34.1"
:: error: RPC failed; curl 56 GnuTLS recv error (-110): The TLS connection was non-properly terminated.
:: fatal: error reading section header 'shallow-info'
:: fatal: Fetched in submodule path '../../../vendor/base', but it did not contain 48193c3894410ad5f60e1c4b8ab7314be53f93fe. Direct fetching of that commit failed.

Fetching and building them locally works as expected though, so I am assuming there is some proxying happening which prevents access to googlesource repos.