Tiaga village generated with all 'taiga_decoration_1' empty (no water, just trapdoors).
Initially, villagers were scattered normally, then one hopped into the trough. Then more followed over time, until there were 7 stuck in the trough.
Environment
Java 20w06a
Seed 6505496499938309914
tiaga village at xyz -1474, 65, 80
This is caused by MC-50556 - they think the vertical trapdoors are closed and try to walk through them instead of jumping over them.