Thank you for alerting me. I did experience this glitch on a private server so that too could have factored in.
Thanks again.
Yeah. My creeper farms roof was perfectly fine in leaves and after 1.14 it now spawns mobs
I can't speak for all farms in question, but I know my farm that has been having little to no spawn rate does not rely on drowning. Mobs drop money on our server, and slimes give great exp, so I have them drop intact into a chamber players can kill them in.
I am staff on a fairly popular server, and our entire server has been having this problem since we (recently) updated to 1.8. Some attention on this issue would be amazing. One of our admins has been running his auto-farm for 2 weeks and has gotten only a stack and a half of slimeballs in that time; whereas before it was very prolific.
Here is the report.