My base only has 4 beds in it. This is intentional so that the 4 villagers I use all the time don't breed unless I want them too. This has worked for the past 2 versions as it's intended. (1.14.4 & 1.15) However; now, in Minecraft Java 1.15.1 my villagers won't stop breeding. I don't have any other beds anywhere. 4 only. I have 2 master farmers and 2 novice or journeyman librarians. They bred randomly a couple times, and I got rid of the babies. But I just had both pairs breed on their own. I now have a base with 4 beds, and the villagers just bred 2 more on their own.

Find the world file linked here:

https://1drv.ms/u/s!Ar3ei-r8sxwQjmoWFe7bqEdklgYK?e=yXrz7O