If this is an attempt to prevent people from suffocating while looking up, that still happens, too. So now you suffocate when swimming up, and it's impossible to build under the water as swim mode can't be exited.
I have just experienced this issue in 13.1 pre-2, and I have never experienced it before (and I have successfully traded with cartographers to find a woodland mansion in 1.12.2). This bug actually crashed my game and my whole computer (Windows 10). It locked up everything; even trying to end things with Task Manager was unsuccessful. Every time I tried logging into the world, even if I do not try to trade, the game crashes. I took the same game from my Windows device to my MacBook Pro, and when I began trading with the cartographer, the game lagged. I saved and quit, logged back in, and the cartographer was gone from the village.
No, this isn't resolved. My harddrive has a confirmed over 300GB free and it is only several years old (solid state). This ONLY occurred once I tried using Minecraft 1.13-pre1, so therein is your error. If you think you fixed this some time ago, then you're very wrong. I see that others who had this error also did not necessarily suffer from a full and or faulty harddrive. Do you want feedback on 1.13-pre1 or not?
This issue is in 18.1. Did or did not Mojang explicitly ask for feedback on the experimental 18.1 release? If there's somewhere else to go to leave feedback, then please leave instructions on where to go.