My position is that this looks like a backdoor but there is no way to know for sure, and I stand by it. If you find it too nuanced that's ok.

Yes, it's not, but my (and his) point stands: it's likely incompetence. It's very biased and uncharitable to immediately assume malice.

Same for me. While others argue that it's "obvious" that the author believes much more strongly that this find is a backdoor and not a dumb mistake (a very easy one to make for a non-cryptographer programmer), I am still unconvinced.

Would be curious to read a statement from Telegram's team though -- not that any team would ever admit to putting a backdoor...