It looks like many others in the forum have reported failures of the snapshot feature. The only posted response I have seen from Steinberg is that snapshots were “fixed in Cubase 12”! Steinberg marketed snapshots as a major feature of Cubase when I bought Cubase 11 Pro. Now they are suggesting the only way to get the feature to work is to pay more money for an upgrade to 12. Wow–just wow!
https://forums.steinberg.net/t/please-fix-mixconsole-snapshots/787682
https://forums.steinberg.net/t/mix-console-snapshot-is-not-retained-fixed-in-cubase-12/128988/25