Me and my friends play on a Minecraft Server together. The world is amplified. When we started the server slimes spawned normally in caves and swamps. After a while the slimes stopped spawning. They don't spawn in chunks where they used to spawn, they don't spawn in swamps anymore and they also don't spawn in "slimechunks" we found with the Chunkbase Slimechunk Finder.
Thank you for your report!
We're actually already tracking this issue in MC-153326, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.