It's been like this for a while, and the project owner's attitude is pretty negative overall. I do use signal daily, but I believe it's likely compromised ala lavabit.
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They could easily add a backdoor in the client despite the fact that it's "open source", because no one builds it from source.
The Signal android build now uses some PKCS11 machinery that requires patching out to build without using a smartcard, but otherwise it works as expected.
I dove into this darkness while trying to fix the borked MMS handling on Visible (a Verizon MVNO), and is the reason I'm generally with you: if someone can't build the project, then it's not effectively open source, IMHO, because I lose my "right to repair"