Latest version I think, cloned from repository with --recursive.
Probably not, in the latest version this assertion is in line 1420, not 1636 in validation.cpp. Are you using "23d3ae7accfc690298b1b0bac9615155f485c5ad" version?
It seems that your client found a node with different Genesis Block. All blocks have block hash starting with at least 32 zero bits. Also, this Genesis Block has a very recent timestamp, 2020-09-03.
Hardened checkpoints does not exist in the newest version, grep shows no results for "hardened checkpoint".